There's a reason for space capacity in the emergency services
and I would greatly suspect that this applies to other users such as the military, utilities etc.
Routine radio traffic on routine days is at a routine level.
If you get a major incident then it goes up at some huge rate, and to be quite frank the current systems struggle (and fail) to cope with very busy periods that are not significantly large emergencies. I was on airwave (OK, I understand that frequencies in this case is not a direct relationship) in London for New Years Eve and the system was regularly overloaded to the extent that we went silent for up to ninety minutes at a time. There was more than one prolonged outage. I've heard an interesting rumour as to why but don't know the truth of that particular one.
Not everything can be done by the data messages that the sets are capable of, and given that our backup is in effect the GSM system which was, as usual for this event, also overloaded its all a bit creaky.
I can recall the days of everything being analogue and confirm that exactly the same problem applied there and for those users still on such sets, the same problems pertain.
There comes a point where you have to decide that some "resources" should be ring-fenced from commercial considerations in the public interest.