A lot of people are stuck with safari on iOS where there's not even another browser since apple bans them.

People choose to download Chrome over firefox, to ditch their custom browser engine (microsoft & opera) in favor of chromium.

We've centralized development effort on a large open source project.

Why exactly is this really really bad?

I find the safari situation bad because I can't use various web standards, it's closed source, etc, but the chromium one doesn't bother me. I just install firefox.