It was somewhat of a special situation back when Gnome 3 dropped. Ubuntu & flavours of it was still regarded as the go-to distro by many and KDE still had a somewhat damaged reputation due to KDE 3 (even though 4 was already available, however that also had some issues). Many environments we know today didn’t exist yet, so lots of people were rather distraught when Gnome broke with a lot of concepts and dropped what arguably was a horrendous DE.
Many of our current DEs are Gnome 2 or 3 forks (MATE, Cinnamon, Budgie, and back then also Unity), made exactly because of this whole debacle.
According to this data, desktop devices still make well over 50% with over 75% in Europe.