No Leadie, you are wrong..again!
UAT requires a transponder to be fitted as well....no transponder no TCAS. No ground station no see by SSR!
ADS-B 1090ES is already a mode S transponder. The TCAS doesn't see the squitter it sees the mode S.
UAT and 1090ES are separate and incompatible. Well, to be precise separate racking. UAT requires a lot of boxes to facilitate and uplink as well as secure lines back to the TRACON in each area to facilitate the traffic transmissions as well as the other data.
UAT was designed by MITRE as a datalink, first and foremost before there was a need for separation purposes.
There is no data uplink with 1090ES nor is there a need for one.
I would like to know the number and age of any airline that doesn't meet the requirement. The only people having a whing are owners of ten year old or older bizjets that fly AIRINC gear that costs a motza to update.
Leadsled, at this point you should be applying your hangar sized brain to ensuring AirServices actually provide the coverage their maps say they do.