I mean......the very first generation of i7s already had a dual-core mobile part, i7-620M was a dual core cpu.

So I'd argue you can't really "ruin" something you've just introduced. I do agree that for a while it was standard that a desktop i7 was a quad core and a mobile one was dual core.

At one point I think hyperthreading was i7 only too?

Mobile i5s always had hyperthreading from the beginning.

Edit: nope, actually, I'm wrong - Core i5-430M was a straight dual core, no hyperthreading part.

Originally, my memory says "i7 meant 4+ core & hyper threading", "i5 meant 4 cores w/o HT", "i3 meant 2 cores (with or without HT)".

But I'm sure even at the beginning there were SKUs that broke the coding due to customer demand.

I think the lesson here is that Intel's marketing for these chips has been a mess from day one.

Some of it is inevitable, they have too many aspects to contain in a reasonable product name, but letting the names become divorced from any sort of reality helps nobody.

I'm writing this on a dual core i3 with hyper threading.

Yes this was so annoying... We optimized software for multi core, but the laptop builders label their products as 10th gen i7.... which says little about it’s performance. GPU labels are easier to decode by comparison.