That's absurd. Firefox has been at parity with Chrome for a long time, both are extremely mature technologies. Sometimes one is ahead of the other in one way or the other, but they are largely identical. The exception is when Google or Microsoft "accidentally" break their websites on Firefox.
It's pure fantasy to insist that the market share of Firefox is primarily driven by technical merit. Otherwise, you couldn't explain why Firefox is still at 20% in Germany, for example.
Firefox also has containers which (AFAIK) Chrome lacks. The UI for Profiles is probably worse, but Containers dramatically reduced the need for them for many (but by no means all) use cases.
It's definitely not the case that Firefox is behind here. I would say they are slightly ahead overall, but which of the Browsers is ahead depends on your specific use case.
It should be fairly obvious that this has nothing to do with the reason that Chrome has 10 times more users.
I've tried containers, maybe something got better, but I just simple, one window with everything in my work profile, another window, everything in personal, it's so easy to use in chrome. I can close the work window at the end of the day, and open it again the next morning, carry on
true. but it is much harder to switch between profiles in firefox, and containers don't really work for all the use cases you might want to use multiple profiles for (like, say having different bookmarks, and settings for different profiles).
It's pure fantasy to insist that the market share of Firefox is primarily driven by technical merit. Otherwise, you couldn't explain why Firefox is still at 20% in Germany, for example.