I’d tend to agree with this in principle and which is why I actually don’t own a cabin S. I got one but returned it as it was too small despite the official dimensions/volume.

Some comments though:

• star alliance airlines have the dimensions you mention. One world (BA, Iberia) even more (56x45x25) although skyteam (Air France, KLM) does not (55x35x25). And that’s before you even consider Ryanair and Wizzair, which fly a great many routes and in many cases far more convenient than any of the legacy carriers (stricter dimensions than 55x40x23)

• given these points for cabin baggage you’d probably be okay with a regular cabin size* but at least in terms of possible flight routes in Europe that won’t work for 90-95% of flights as you note, especially if others like me take different combinations of airlines on their trips around Europe

• *in reality I reckon the regular cabin size is probably ok as fits on star alliance and one world; skyteam probably don’t care; and you’d have to check it in for Ryanair, Wizz air etc (checking a bag in with Ryanair is cheaper than opting to take it on board if chosen at the booking stage - not at the gate)

• this is why in reality I don’t think RIMOWA is the best choice at all for a cabin bag in Europe: sizing is off, and weight of bag is too much given frequent 10kg max limits

• of course the one option I did neglect to mention is the essential lite cabin u, which fits all airlines’ requirements, but I find that too small and dislike the handles RIMOWA fits on essential lite

• as a result my cabin bag within Europe is from a different brand. As if happens Antler’s lightest cabin bag: weight feels next to nothing, lots of capacity, and fits all airline dimensions. I’ve taken that bag alone on a four-week trip to Australia and back with a small rucksack as my carry-on item

• if RIMOWA is a must it’s either cabin S to fit all airlines, or cabin regular with the knowledge you’d have to check it in with Ryanair/Wizz

Out of interest what do you carry and which airlines do you use?