While it's perfectly understandable why you've responded to the changing environment of startups, the lack of holding a position for long enough is a career-limiting move.
It sucks, but the world isn't fair.
That's a weird thing about resumes... they're pretty much for life, so any move has to be explained/justified over and over again one or more decades later.
Any short-term quick win to get away from a bad boss of a few thousand $$$ could stop you from getting a great job much further down the track. Any move should always be thought of in terms of "how will this look on my resume?" (which won't show salary, office environment, etc.) and "how can I explain this?". "It was a good opportunity to learn about XYZ, which they didn't have at the previous company" sounds great. "I had to get away from XYZ" or "I wanted more job security" don't sound as good, especially if XYZ or the fact that the company was a startup with limited job security was evident from the start.
is it though? I see people hoping all the time. Sure you're bound to run into a situation where somebody will view that as a negative but the only way you can switch jobs every 2 years is if somebody hired you. Which means that by definition, there will be companies that don't care.
I guess in a tightening market you'll have more candidates without job hopping so you can use it as a criteria but if your company has legitimate vertical movement there's probably less to worry about. Of course though if you company staffs its ranks pretty entirely by hiring outside as opposed to internal promotion then you should expect to replace the role in a couple of years.