lol let's not pretend that Apple has limited resources though. Apple has a very limited amount of core developpers (e.g webkit being abandonware) and they are probably mediocre on average but obviously this is artificial scarcity.
[edit] source: https://github.com/WebKit/WebKit/commits/main
gecko has 782,002 commits
chromium has 1,080,253 commits
To help you understand the magnitude/impact of this difference, a single 100K commit difference account for more human resources than a whole native GUI framework (e.g cocoa, gtk 72,090 commits, QT ~80K) has received in its lifetime now multiply that by 8 and you get an idea of how obscolete webkit is regarding human resources. They might ? have hired more devs recently but if true, it's already a decade too late.
finally the gradient is not closing.. ten time less weekly commits: https://github.com/WebKit/WebKit/pulse https://github.com/chromium/chromium/pulse