I go back and forth on this one.
On one hand I think it would make things much simpler for users who have enough storage and bandwidth.
On the other, when there is a vulnerability in a major library we would have to wait for every application to be updated, if they're even being maintained.
The thing is that package managers have mostly abstracted away the headaches of dependency hell, but have also raised the barrier to entry, so any software not participating seems suspect.