There is a lot you can change on guitar. The wood species (including plywood) can get you 50 different models from otherwise the same patterns (there are hundreds of different wood possible, but not all of them will be compatible with your patterns - either not strong enough for the thickness, are known to sound bad and so not tried - Luther books have charts of pros and cons of different woods). You can put several different pickups in it (including none) Then you can put a few different styles of truss rod in, tuners, cover with one of a dozen different finishes - it is easy to get over a thousand possible combinations then select however many.

That is for just one pattern, but there are many different patterns. Then we get into acoustic vs electric.

Of course it isn't hard to create a new alloy for your cymbals either. The real question is how many different models is it worth putting into your catalog. There is a cost to each one - even if it never sells you have to be ready to make it which means keeping anything specific to that around (or at least have suppliers that commits to making whatever you would need on-demand)

This is correct, but AFAIK if you buy, say, a Stratocaster, it can come in a number of different colors / finishes, maybe with a couple different options of wood for the fretboard, possibly a couple different options for the pickups, but this is still the same model.

I suppose that the cymbals makers just cut their models more thinly.

They have different factories in differente countries with different quality and price points. Also electronics have tiers.

It's surprising how much there is still a difference in cheap and expensive potentiometers and switches. One would have expected someone to have cracked high quality and cheap by now?

Different neck joints would spawn different models with ease.

I wasn't suggesting that there aren't a lot of variables for guitars. Possibly more than for cymbals. My point was there is a lot of variables for cymbals even if it's perhaps less obvious.