Our house, purchased about 15 years ago, has three toilets. Not sure how old they are, possibly as much as 25 years old now (in 2021). They were somewhat prone to clogging unless you were careful about how much toilet paper you used.
We replaced one of these toilets in 2012 with a Toto toilet. It’s an extreme water miser, but in all the time since then it has never clogged, and always clears the bowl completely with a single flush.
It also has the CEFIONTECT coating (formerly called “Sanigloss”), and does seem to resist marks pretty well.
In the U.S., in the early 1990s, a Federal law mandated that residential toilets could use no more than 1.6 gallons of water per flush – prior to that, it appears that toilets here may have used several times that.
The first generation of “low flush” toilets weren’t very good at compensating for the lower water volume in a flush, and I suspect that those are the ones that became infamously prone to clogging (or requiring multiple flushes to clear the bowl).
Newer designs use “pressure assists” and other engineering techniques to generate additional water pressure, and are much less prone to clogging. We installed a new Kohler toilet, with a pressure assist, in our main bathroom in 2008, and that toilet has maybe clogged twice in 13 years.
Ironically it seems like this is turning into a pissing contest.
I guess if bob_2 wants to know if clogs are more common in the US, a poll will be required.
ETA: it seems a couple of the ninjad responses explain why there may be a perception of US toilets blocking more.
I haven’t had this kind of blockage. Maybe I’m defining blockage too broadly? I was just thinking of times where someone has left a brown anaconda that needs assistance getting round.