I'm not suggesting that no one should floss. The opportunity cost is low. You have nothing to lose by doing it, other than a couple bucks spent on floss. It's similar to multivitamins, the evidence on the benefits of those is also low quality, but the most you have to lose is a couple of bucks.

In theory if you think in an evidence-based way your positions on flossing and multivitamins should be about the same, which is interesting.

What's really important though is that the profession of dentistry has not felt the need to fully study and establish the benefits of one of their most foundational recommendations.

Every dentist tells you to floss yet they have not bothered to establish reliable evidentiary proof that it works. If they don't care about evidence when it comes to flossing, what other procedures are they pushing without solid evidence of benefits?

The hot take way of saying this (and I do kind of believe this) is that dentistry as a medical science is in its infancy, and as a result, dentistry as a profession/business is partially snake oil.

All that said I have had one crown including a root canal done in my life, the need was clear and it was done well and professionally and I'm happy with it. So I'm not saying that everyone should ignore dentists but this imho is an important place in your life to consider getting second opinions and steer towards professionals who are less profit-driven when you can.