For the TdF, neutral support isn't really an issue with the cars. Froome's jogging was probably the last time someone took a bike from neutral service, and that was such a freak accident it'll probably be 10 years before it happens again. Generally, if the neutral service car is available, there's a team car not far behind.
It's a major issue for the motorcycles. The motorcycles are usually the only ones available on the steep climbs when the race is on. Between front & rear wheels, the various axle standards, and 11 & 12 speeds it's a nightmare. I have a feeling Shimano is going to have just grab a wheel set from the top 3 GC riders, and for everyone else, good luck. If there's some overlap maybe they can support some other common ones.
A motorcycle can carry probably 6 wheels, so that's likely 2 different front-axles options, 4 rear wheels (11-speed x 2-3 rear axles, 12-speed x 1-2 rear axles).
In some ways this is largely inevitable, the diversity of the peloton is shrinking dramatically. Out of 22 teams at the last TdF it was 3 Campy, 2 SRAM, 17 Shimano. Campy will probably get decent neutral support because Pogacar is defending champion. If you're riding for SRAM, keep riding a flat until the team car gets to you.