I live in Southern California where there was no shortage (until recently, at least) of very early-stage startups, and for years I exclusively used startup-focused sites like AngelList (now Wellfound) when jobhunting. The largest startup had 12 people when I joined. I worked for a company of 40ish once, but they weren't primarily a tech company and engineering consisted of only 3 people.
I should perhaps disclaim that while this worked perfectly for me for close to a decade and I was never without work for more than a couple weeks at a time, I have currently been unemployed for a few months and have had a considerably more difficult time than at any point in the past.
Going with, in general, a company with less than 50 employees doesn't have to meet many of the requirements larger ones do when it comes to things like the FMLA.
Yeah but the demand for talent was such that, for at least a long time, the benefits and perks at startups usually exceeded those of the bigger companies. This may not be the case now, but I still think what you describe is not true often enough to be considered a general truism
I should perhaps disclaim that while this worked perfectly for me for close to a decade and I was never without work for more than a couple weeks at a time, I have currently been unemployed for a few months and have had a considerably more difficult time than at any point in the past.