And it doesn't have to be a startup, it can be any job that you become attached to. I assume it's a mix of pride in what you have achieved and the parenting instinct.
Your suggestion is insulting to many, many people who really do care about what they are working on.
Especially, I would think, in companies that received millions of dollars of investment from outside sources (VCs). (In exchange for amounts of control by those same investors)
Pride of creation is one thing, but I would caution you against using this as a blinder: the corporation is not (and can not legally be) loyal to you. [Edit: unless you provide more shareholder equity then the next person... and then only until the person who increases shareholder equity more than you comes along]
Ironically, this is precisely what those who seek to instill a misplaced sense of "loyalty" to a corporation want.
For stock ownership in a startup it makes more sense as they have to stay PLUS contribute to the companies success.
But that loyalty is tied only to people, not to any company. If I'm not in a job because of loyalty to one or more people, it's got to be out of either economic factors, or because I find the work interesting/fulfilling. The entity it's associated with is irrelevant.
But I never said loyalty to abstract entities didn't exist, the implication is that it's horribly misguided.
But then why is that loyalty misguided?
How does it particularly different from loyalty to people (which you seem to think isn't misguided)?
Relationships between people rely on more flexible rules: networking, camaraderie, common ground. A psychologist would say that these are a trade of "services" of a sort, but since nothing is inked, loyalty plays a stronger role. Unlike a business, it is not unheard of that a person sacrifice their welfare/life for their spouse/offspring.
It is misguided to expect the type of loyalty in the latter in the context of the former.