You forgot the road themselves. Note that Illich also refuse train, so you have to build them with all logistic to build them on bicycles cargo.

On top of this, the ambulance we know how to build today are not the one from when we first managed to go faster than a bicycle (average human).

Which means you would be stuck at state of the art engine, car, brakes, etc from the 30s. Or maybe the 10s even, as it was already valuable in first world war.

Same for planes. Trains. Etc

And would we really build the infrastructure for them to actually drive on if it was so limited?

As the other answers point out, this fails to acknowledge the systemic impact of such rules.

My usual test for a lot of critics of current systems that offer something "far better" with nearly no downside compared to the current one is to ask if they could invent, develop and produce MRIs in enough quantities.

It is actually really hard to build systems that would. This is a taller order than you think.