That was one thing I was thinking 3d printing would gut with respect to that type of gaming. But from what I have seen it did not really stop and the 3d printed stuff is looked down upon.
GW’s minis are expensive but they are good, fantastic even. They don’t have a monopoly, several other companies also sell very good minis, but injection moulding is expensive so scale matters here.
So sure, printed minis are better than Warhammer minis from 20 years ago, but none come anywhere near the good recent ones. The main thing going for printed minis apart from price is that it’s easier to have different poses and add some variety.
Also, a lot of people play games hosted in GW stores, and i believe GW have a policy that you can only use their minis in their stores.