As a cyclist and avid fan of pro cycling, I don’t see this being so useful for transportation from a dropped position back to the peloton or breakaway. As others have noted, team cars help, and often the distance to close can be handled by one teammate. I forget which stage, but this year when Vingegaard had a mechanical and needed to swap bikes, Visma didn’t have any domestique wait for him! The protected rider is usually the best rider.
I was thinking about how this might be useful on the attack. Visma had several super domestiques remaining at the end of the tour (Jorgensen, Kuss, Simon Yates) and UAE had lost its top lieutenant. Could they have made a 2x2 train for Vingegaard? Well, maybe, but Pogacar would’ve just hopped on board. So not sure we would see this either.
Amateur rides with no cars and a wider divergence in cyclist abilities, maybe this is more useful.