Yes, stupid because...
The idea isn't without merit, but as it stands it won't work. The only sensible solution is a wholesale company that runs ALL the base stations and whose licence says 99.5% Geographic (not population) coverage and minimum capacity standards (thus mast density has to vary with population and not just the current scenario where mast density is based solely on ROI vs capex. Like SES-Astra runs the Satellites that Freesat & Sky use.
Then every one else is a MVNO.
It's a RAN.
It would also on average double capacity because you wouldn't have the stupid situation where at one location your speed is 0.12bps or you can't connect or make a call, on ONE operator, but the other operator's channels are sitting idle.
The problem is weak regulation from Ofcom, who supports operators against the consumer and a totally blind devotion to idea that competition is always good. It's not like baked beans. There is limited spectrum. The real reason to have multiple operators on the spectrum instead of one Wholesale RAN operator is to get more money in licence fees. The RAN operator should pay NOTHING for licence and the revenue raised from the retailers (VAT gets a lot already).