There's the problem. You're thinking of these as being lifeboats ejected from the spacecraft. That wasn't the case. The idea was that everyone would climb into these inside the failing spacecraft and then someone in an EVA or IVA suit would pick up the balls, clip them onto a lanyard, and pull them out through the airlock. That's why they the Spaceballs didn't have any propulsion systems on board; it would have been dangerous to have hypergolic or cold gas thrusters stowed inside the Shuttlle.

If the idea sounds super sketchy to you, you're right and NASA agrees. The technology never flew because of the first limitation you mentioned (no way to launch a second shuttle fast enough). The emergency plan was, IIRC, to don IVA pressure suits (the orange ones they used at launch), search for the leak, flood make-up gas to keep pressure in the cabin, and abort to reentry. In the event of a rapid depressurization the make-up gas couldn't handle long enough to don IVA suits then we would have renamed a bunch of high schools. That was the reality of being a shuttle astronaut.

The abort plan for the ISS is almost precisely what you describe. Whenever anything major goes wrong, (fire, leak, etc) they can pile into the abort spacecraft (Soyuz or crew dragon), and abort to reentry if the situation cannot be controlled. There are always enough abort craft attached to the spacecraft to hold all of the crew aboard.

(I am not an expert on this topic.)