Them memory leak on Gnome shell is fixed on version 3.28.4 for me. It was memory-leak on Ubuntu 14.04 but they fixed in 14.04.2. The "a decade" claim needs some evidence.
This mismatch between compiled code and javascript existed from inception to now. The fix if I understand it correctly is to really aggressively free memory in a fashion that appears grossly inefficient but in practice performs acceptably.
The release of gnome 3 was in spring of 2011 the "fix" was released in spring of 2018. It would be more accurate to say that it was terribly broken only for the first 7 years of its existence.
Because their "fix" is a hacky workaround for the fact that the only true fix is to throw everything away and start over the bug is actually back in 3.34
https://gitlab.gnome.org/GNOME/gnome-shell/issues/1740
This brings us to an 8th year of shipping a broken product heading for year 9.
That this was a bug that sprung into being in ubuntu 14.04 and was fixed in a point release is totally incorrect.