I've interacted with a lot of reasonably randomly selected companies after starting a consultancy last year, and honestly yes, 80% of software developers are incompetent.

It's honestly a stretch to say they're software developers as you're probably imagining, but if you walk into a random office, most people with that title won't use version control, won't ever ship, and are generally a bit concussed.

It can be hard to imagine because many times, when we find competent teams, many of the members have never directly experienced a truly average team, as the culture one acquires on those teams makes it hard to ever be accepted on a good team (frequently the weaker developers don't even understand there's anything lacking in their skillset).

I'm more sympathetic now than I was a year ago, but it's also pretty unacceptable when you remember they work at hospitals and the government!