There are other options, including TPUs. Besides, cloud computing is what any sensible practitioner uses, despite how building a home rig is a fun hobby.
I agree that most teams just use cloud compute. But if you're a startup that wants to not burn crazy amounts of money, then a home/office rig is definitely the way to go. A month or two worth of training in the cloud will cost the same as a V100.
Yea, large companies that don't really care about operational spending will happily use GPUs. But for anyone else, spending a few thousand on GPUs will save a lot of money very quickly.