Yes they are absolutely still a thing. Albeit the amount of work available has been in decline for decades and it's now a fraction of what it used to be, but t

Yes they are absolutely still a thing. Albeit the amount of work available has been in decline for decades and it's now a fraction of what it used to be, but there's still enough work to keep a core of the very best working almost full time in the remaining major recording studios (here in London at least). I think you'd be surprised at how much music is still produced by composing, arranging for and recording real musicians. But London is still one of the best places on the planet to get that kind of work done so it's an admittedly skewed experience. Oh, and there's more than just session musicians who need to sight read perfectly first time - that's just table-stakes for professional commercial musicians in my experience (source: am professional-level jazz trombonist).