Can't see how there's enough market (or capacity) to support Eurostar, Trenitalia and Virgin.
I wonder whether it's a front operation for DB» , Renfe, or just an opportunistic play to get licenses and trains in play which can then be auctioned off to the highest bidder?
The trains for TrenItalia France appear to be common type (Hitachi made Frecciarossa 1000) as used on Paris-Marseille, Paris-Milan etc so could easily be reallocated.
Obviously the market will determine the volume (within limits) depending on the ticket price
Ouigo, Iryo, Avlo in Spain have some tickets below €20. Of course operating costs with channel tunnel, and security will be more, but if some tickets are nearer £50 then clearly volume will be much more than current expensive fares.
My own hunch is TrenItalia will try and build market share from its 2029 launch, to get a foothold before Virgin starts year later, and before Eurostar gets any new trains.
It would of course be possible to reinstate or add security at the stations with International platforms currently not used by International trains (Stratford, Ebbsfleet, Ashford). And I could easily forsee Stratford getting trains, indeed I have even seen a suggestion that TrenItalia intends to use Stratford, then run empty to the Camden spur for reversal to avoid St Pancras fees. Presumably there is trade off between St Pancras fees and cost of staffing Stratford International