They were a lot faster, especially the laptops. And that was really the consumer proposition in both cases - you put up with our switch in exchange for a faster, better, stronger computer.
If Apple ends up doing it, the proposition would almost certainly be different and it seems very unlikely it would involve things like running your x86_64 macOS apps on your brand new Mac except three times slower. Thinking about this in terms of previous changes (or in terms of PPC history details) just seems obviously wrongheaded to me.
People assume that everyone who uses a Mac is running Photoshop or developing advanced AI but they're not. There are a lot of professionals using Apple products but they avoid the low end like the plague. Apple is a lifestyle brand these days and much of the user base has no demand for anything beyond the core Apple Apps.
The Macbook Core i3 is barely enough to run Safari or iTunes and Apple could probably replace the CPU without many of those users ever noticing.
If Apple ends up doing it, the proposition would almost certainly be different and it seems very unlikely it would involve things like running your x86_64 macOS apps on your brand new Mac except three times slower. Thinking about this in terms of previous changes (or in terms of PPC history details) just seems obviously wrongheaded to me.