Before this turns a molehill into a mountain (or the other way)....
CSP/CTS installed ICALL/ITAC repeaters at several CTS/CSP sites in the state when the CSP 800 system was installed. When rebanding came along, they were rebanded. I believe one or two additional sites were added along the way, but that's about it.
Around the time NIFOG was introduced (roughly happened to be the same time as rebanding took full swing) the non-rebanded ICALL repeaters kept its ICALL names, and when rebanded, took on the new 8CALL names.
States, counties and cities that had legacy ICALL repeaters just rebanded. Some states never had them, or never will on the statewide level due to their requirements (western states on VHF never had a need). Metro areas may or may not have them if they had an incumbent 800 system.
When federal money was flowing, some did add a repeater or consolette or two.
There is no requirement to have these radio, or anything on the U/V TAC's.
Connecticut in the late 90's, via the CDOT issued 800MHz radios initially on ICALL and TIMS channels IIRC... I had to pick several up in Wethersfield. As the CSP system was maturing, the state issued every PSAP and consolette with the ICALL channels and 95 SPAN for access to the state system. They also issued 800MHz MTS2000's with ICALL (then reprogrammed to 8CALL).s to each PSAP.
Even further down the road, when they took the MDT data off the radio and used commercial cell modems, the data channel was repurposed into a statewide analog repeated 800mhz channel. This does not require any intervention with the NCC.
NCC does monitor the 8CALL channel and enables/disables the 8TAC/8CALL repeaters statewide as needed.
Various state departments, federal and commercial entities "encourage" programming of every mutual aid channel known to man, but nothing is really mandated. Where I am responsible for comms now, I have about 5 zones of mutual aid channels whereas we only use 1, maybe a 2nd zone for day to day and intra-mutual aid. Drives the users nuts.
That's all there is to it.