If I'm just coding up a small app I don't want the overhead of a framework. I might want a bit of routing, possibly some automated mvc and that's about it. Everything else in a framework I usually care little about and just slows stuff down for no benefit to me.
Coding up a "framework" that does only the very little I actually need is fast and very little development overhead considering the number of times I've done it and the fact that I've got code I can re-use.
This isn't business advice however, it's just my own personal project preference. If you're running a business you want to be able to replace developers if they quit so it's often a better idea to go with something more mainstream like a well known framework so that ramp-up time is minimized.
c) No single developer 'owns' any part of the code
That should ensure that your developer team's "bus number" is reasonably high.
Finally:
d) You treat them at least well enough that you're not in danger of the entire team quitting at once.
That said, it can still be useful for many reasons if they base their work on F/OSS code (languages, libraries, tools, frameworks, etc.) that has a reasonably-sized community around it. But if the developers you hire are good that is very likely to happen naturally.
There are always circumstances where writing your own may make sense in the short-term, but unless it has something to do with your business' core-competencies, or otherwise leads to a sustainable business advantage, you're usually well advised not to bother.
If I'm just coding up a small app I don't want the overhead of a framework. I might want a bit of routing, possibly some automated mvc and that's about it. Everything else in a framework I usually care little about and just slows stuff down for no benefit to me.
Coding up a "framework" that does only the very little I actually need is fast and very little development overhead considering the number of times I've done it and the fact that I've got code I can re-use.
This isn't business advice however, it's just my own personal project preference. If you're running a business you want to be able to replace developers if they quit so it's often a better idea to go with something more mainstream like a well known framework so that ramp-up time is minimized.