Hitting a nerve...
You can address every technical issue with two things: spectrum and money. It's really that simple.
Then we have the human element that we must consider. It's not as simple as the technical part because we have:
Politics, ego, turf, planning (or the lack thereof), training (or the lack thereof), and NIMS - specifically adopting it on paper in order to meet mandates, but never really using it every day or establishing joint operations under a unified command.
Mondaro's, Rockaway's and e911god's experiences all point back to the failure of the latter, because even if there was so-called interoperability, some of the people who were there had a silo mentality. Take an objective look at Rockaway. No bashing, no armchair quarterbacking, just a look from the outside looking in. The NJSP established a policy. Great. Rockaway established a policy. Great. Each developed their policies independently and, with a high probability, without awareness of (and possibly without regard for) the other's policies. This is one breakdown. Each agency apparently trains and operates independently. I believe that both the trooper and the fire company were both well trained and fully competent. Both were also concerned and were defending their policies. And the lack of offline human interaction caused it to go bad. Who won? It all looked bad to the public. Arrests were made or people were detained, positions were defended and in the end, the chief and engineer were more than inconvenienced and the trooper had to "take a ride" (in NJSP parlance, he was reassigned to the other side of the world). If a preexisting relationship of joint policy development, teamwork training and everyday operation in a unified command environment would have been the norm, none of this would have ever hapened.
My contention is that even if you have "interoperability" as a technical capability, the only way it would get used is for responders to embrace teamwork rather than act separately as individual components who just happen to be in the same place. If you have it and never use it, but expect everyone to be ready to go when it's "for real," the whole thing will become a galactic charlie foxtrot at best.
It's best to work out these issues before anyone ever has to respond. If there is an impasse on anything, those things have to be straighteded out or someone has to contract with someone who can work with whatever the inflexible situation is.
My hat's off to e's old chief.