While I think shareholders can be a driving factor, I see it way more often with VC-funded companies. The "2.5x year over year" growth mantra that places like YCombinator stipulate have disastrous effects on small tech companies. Often, these startups have an incentive to keep taking additional funding rounds, which appears to tighten the grip the VC has over them.
Try growing the next Microsoft or Google or Amazon out of that model. I'm not convinced that it's possible. At least if you bootstrap your own company, you don't have the same binding obligations...even if it takes way longer to get to a place that's self-sustaining.