Beyond smoking rates plummeting in recent years, indoor smoking rates were plummeting for years before that, and that's when you normally saw ash trays. I was a smoker for a couple of decades and never once had a dwelling I smoked in, and that was true for many other smokers I knew. That became socially frowned-upon long before smoking lost its momentum. I have noticed that even the dubiously effective large smokeless self-extinguishing public ash trays that were ubiquitous outside of bars/clubs/etc in the 2010s are becoming less common.