Around here people are Sativa crazed. We have every strain known to man in Vancouver, but most people (including the young crowd, and the newcomers via "legalization") want Sativa. We have not noticed any decrease in available Sativa genetics, here at least!
We generally don't notice the same difference between "Sativa" and "Indica" strains that most people do. When it comes right down to it, their differences are mostly cultural/historical, not physical. They all have the same cannabinoids and terpenes, just in slightly different proportions, and all come from the same species of plant Cannabis sativa. There ARE differences between the strains, no doubt there, but we don't believe anymore that it's as simple as "sativa for day and indica for night" like we used to. That simplistic view doesn't seem to pan out in the science from what we've read/seen/done.