Should I let the dentist pull all my 73 y/o Moms teeth?

This can be a reasonable treatment plan if in fact the teeth are in very poor shape. It is wise to eliminate current or potential sources of pain and infection. Snap on dentures will require implants. Probably 4 at least in each arch, upper and lower. This is an involved and expensive process Like you said, expect 6 months at least for the implants to integrate into the bone before placing the final denture. Things to consider for making your decision are:
1. Moms health. Diabetes, smoking, etc make it more likely that an implant will fail.
2. Moms mental capacity. This process is a big change and requires adaptation and patience on her part. How does she deal with change? Does she have dementia?
3. Finances. Make sure you understand all the charges up front. What is included now and what might be a future charge.
4. Ease of access and transportation to the dental office. This process involves many appointments when everything goes well, even more when slight adjustments are needed along the way.
i dont mean to sound discouraging. It could be a great answer for her! Just be aware of what is ahead.
(I am a retired dental hygienist of 35 years).

Your haven't mentioned what your Mother's overall health is. 73 is still pretty young and if she's in good health and has many years ahead of her this might be a good idea.
But it is a very extensive and expensive plan. The cavities definitely need to be fixed. But a mouth guard to prevent grinding will save the teeth from further damage, be much less expensive and have no long recuperation time.
Before deciding to remove all her teeth I would definitely seek a second opinion.
Good luck to you both.

IMO, at 73 she should be able to handle the procedures, IF she is mentally competent!

The plus to having the work done now is that you know going forward her teeth are only going to get worse and as we age, change becomes harder to adapt to. If she has this done now, the hope would be that she will be well used to them by the time she starts the dementia slide.

I gave up and had the rest of my aggravating teeth pulled at 62; implants were not an option, because it would have meant driving 60 miles each way to the dentist quite a few times and it was winter. Instead, I had that dentist make uppers - that fit and work wonderfully to this day, 7 years later! My only issue was that when it became imperative that the bottoms be done, I had to have our local dentist do them, and they never fit well; which my original dentist had warned me of. Am planning to finally go back to him soon, before winter, and have him line the uppers, since they are getting a bit thin, and make me a set of bottom teeth; he's good, hopefully we can get those to fit and work as well as the uppers! I DO recommend dentures when it becomes necessary, especially if you can get the whole set done by a dentist with a good reputation for making teeth. There should be way less visits and expense than implants, not to mention problems for your mom. Also, people tell me sometimes I have beautiful teeth - even tho I'm only wearing the uppers; they can't tell, and they look so real....

Something that hasn't been mentioned so far. I she was on Fosamax because of osteoporosis, she may not be a candidate for implants. I took it for 7+ years and there is a real possibility that the bone will not grow back around implants.

I would get a second or third opinion. If this one dentist is going to do all the work himself I would be concerned. It just isn't done that way now. That is why we have all those specialists.

Does your mom have any cognitive issues that would cause her to not comply with the post-teeth removal care? Or other health issues? Tooth extraction is painful and can have complications. She has to stay on a soft diet for about 5-7 days afterwards. If she goes through with it make sure the dentist DOES NOT give her Clindamycin or Cipro as antibiotics -- they can often cause side effects in the elderly (my mom's ankles swelled up huge and painful from the Clindamycin).

I had all my wisdom teeth pulled in my 20s, and was in real pain for over a week. I couldn’t open my mouth wide enough to eat solid food or clean my other teeth, and had to scrape my tongue with a flat teaspoon. (Mind you, the teeth were shockers.) The one thing Patrice the dentist hasn’t mentioned is pain for the victim! Later I had a molar implant, and that wasn’t much fun either.

Yes it will alter her appearance when she is lacking dentures. My DH had to get a new set of dentures, and looked like a parrot for a fortnight while he was without. He self-isolated back then, for vanity (justified at age 65).

For a few years I used a dentist who seemed always seemed to be finding something very expensive to do. I got unhappy, particularly when he did not mention the two new crowns he had suggested at the previous consultation, and found a new dentist. Is yours the same dentist who didn’t give her a mouth guard earlier? I would now always get a second opinion before going ahead with very very expensive treatment.

No doctor would do any oral surgery on my 92-year-old mother's bad teeth because of her heart condition. General anesthesia risk may have killed her. Pain medication was her only option, 'til her natural death three years later.

If she's hesitating, postpone the appointment. She is allowed as much time as she needs to think this through.

Bruxism, is it called..? Anyway - what other options has she been offered? Has she tried the whole gamut of gum guards and retainers and all the other gadgets?

Have you considered getting a second opinion? Or ask about getting advice from a dental school if there is one in your area.

I had one tooth replaced and even with good insurance it cost me nearly $2000, months of pain while it healed. I would do it again but it was very costly and time consuming with a root canal, extraction, implant, healing, getting the cap made, then getting the cap fitted. In all one tooth took 9 visits to 3 different dentists!

Which makes me question the financial aspect of this, is all of this done by one dentist? My regular dentist would not do anything but the cap, he said he would rather send me to specialists for most of the work, so he had no financial stake in the decision.