10-20%* I would actually say (but obviously know what you are saying) and completely agree with your post in general.

10-20% may even be low, they are typically companies profiting on desperation.

This is going to sound salesy coming from a realtor but in this low inventory market you could sell your house within 30-40 days for actual market value. And even those cash closings are going to take 2-3 weeks because of title work and other excuses. I’ve heard those companies go under contract then try to beat you up again on price a day or 2 before closing because of some “issue” they discovered.