I’m sure there’s differences between various region & brands, but from my local grocery (Midwest US), brands I’ve tried (“Chobani” Greek yogurt, and… can’t remember the last sour cream I tried, sorry) do indeed taste similar in taste and texture.
Yeah, for sure they’re not exactly the same, but just like training oneself out of using too much sugar, salt, trans fat, etc, I find that one can shift one’s palate over time. Indeed, when I eat out at a Mexican place or whatnot, the sour cream tastes oddly ‘heavy’ to me, which makes me glad, since part of why I switched over was to improve my diet.