One of the main reasons the Red Cross maintains low band radios is if they are deployed to a disaster area the local trunked system towers and cell sites may have been damaged by the disaster itself, yet they will still be able to communicate with the low band simplex radios.
Local public safety systems need to be aware of this too and have a backup system that does not rely on cell phones and trunked systems.
Think about it. A tornado just went through your city and wiped out the radio towers and there is no power. Will your radios work?
Completely agree with you on this issue. Unfortunately, theres been marketing misinformation, often leading potential consumers of a new, complex trunking system to believe that there's little, if any need, to maintain any kind of secondary backup system. Municipalities don't want, or don't think they need to have a redundancy to the primary, ...too costly, one less thing to maintain & deal with, etc.etc.
We still maintain availability of the entire gamut of frequencies from low, through T band, as well as the interop 800s, in case there's some need to utilize them locally and regionally, in addition to our own system. And, more often than not, there's a lot of use on these (somewhat 'depreciated') frequencies initially, until things fall into place.
Ironically, (& unfortunately), depending on what region and district personnel are assigned to as their AOA, there's still some local systems that won't even allocate tg's /keys to permit accessibility to their system; hard to believe. Last spring on an event in the southern part of the county, a local EM absolutely refused any access to their dmr system by our agency, which led us to open a contingency plan of multi band, cellular and hard-line relays to patch in, until the bosses 'worked things out' to resolve things (...oh, to have been a fly on the wall for that!)...