"Calling out" gnome for needing extensions for customization seems stupid when those extensions are easy to find, easy to use, and work really well. On the other hand, I have not been able to find a taskbar for plasma that would let me group windows from an application together while also letting me rearrange the windows inside of a group. I know I need to try implementing it myself someday, but I feel like gnome ends up having more options.
It's not about how many extensions there are. It's about half of them breaking with each new version. Unless you like outdated systems, in which case you are fine.
I am always on the freshest Fedora Workstation, and all the extensions I use are always supported from the start. I don't use that many to be honest. But, is extensions compatibility really an issue nowadays?
It really depends on what you want. My experience with Gnome extensions has been rather frustrating. For example, finding a working and maintained extension for app indicators is a pain - and you have to do it again for each new release when inevitably the extension is no longer updated.