However, the issue is, any moderately complex application will soon develop its own in-house Framework. Its the natural progression, very soon the head Dev will say "lets create a library to handle all our form validation requirements....lets create library separate UI from business logic...etc"
That's the real "slippery slope" from a management perspective.
Do we wind up developing our own in-house Framework which our current developers are very productive in (but new hires don't understand)? Or do we bite the bullet and opt for an already existing Framework that already has a dev community? I'm not suggesting its an easy answer as there are pros/cons to each. In the end for 90% of cases I think starting with an existing Framework (or at least "Framework-lite") is best approach.