omitted TLDR: some of the above can only be done by paying people money to do them. Company needs income for that.
omitted exibit: why haven't Gimp thrown Photoshop, Pixelmater and others from the throne. If programmers were the only people needed, then all those commercial image editors would be gone from the market. (but a unix shell only needs programming by a single person, so there are no commercial successful unix shells)
The quality of it might be because some real company was using the project to do daily work (even before the ui overhaul).
The most successful commercial unix shells are graphical shells shipped with operating systems. Most users consider the visual function of these shells to be the actual operating system. I.e. "MacOS now has scrollbars in preferences!"
MacOS, iOS, Android all are good examples.
To build a shell of commercial value you end up having to do a little more that a command line shell does.
BTW, the biggest part of Adobe's value prop is AdobeStock templates, fonts, stock art and stock video. This makes it really easy to start a project and get to done quickly.
It would be interesting to see some of the third party marketplaces like Envato, Issuu and CreativeMarket plugins for open source products... And non-Adobe products, too (Affinity, love the products! Badly need a way to quickly get a few hundred templates in there... Corel, your ecosystem is a dumpster fire)