Why aren't more bigger/experienced investors doing this?

Can be profitable ,BUT, my experience as a hard money lender is that there are many companies operstimg in this field that aren’t very stable financially.  

Since refinancing and investment income (like rental income) usually aren’t seen as earned income, it likely won’t affect your mom’s survivors' benefits.However, if your mom’s survivors' benefits are based on disability (SSDI), then additional financial or property assets could trigger a review, so you might want to consult a CPA or financial advisor to be sure there are no unintended consequences.This isn't legal advice.

And if they don't sell their house aren't they going to be in trouble?

Those “gurus” aren’t the ones dealing with the headaches when a tenant stops paying or a property management company ghosts you.

If you know already you aren’t in a position to operate the STR at the level needed to be successful, I would focus on LTR and getting experience and look to do a STR later.

I hope you aren't being pushed into EVs that won't work in winter.

That is what you're doing - you aren't collecting the money, and you aren't benefiting from it. 

Facebook brings in a lot of volume but you usually need to weed out a lot of people that aren't serious.

**Plan B: Refinancing and Renting** - If you aren't getting the price you want, refinancing and renting the property could give you time for the market to recover.