British TV, especially BBC and Channel 4 have always been exceptionally good at knowing when to kill off a series at the right point. Just compare the difference between something like the UK Office vs the US Office or the BBC version of Sherlock vs the US version called Elementary.

Another example, the BBC Series the Bodyguard (a different concept but similar enough) or Israeli Homeland vs US Homeland. The US has made the mistake on a number of times of taking a great concept and dragging it out too long. Maybe one of the few that was justified was House of Cards, where the longer US version was (arguably) better than the UK version...

Sherlock is probably not the best example of a British show stopping at its peak.

Interesting choice of examples IMO.

The US version of The Office is apparently by far the most watched show on Netflix (US). Even if you acknowledge it went on probably one or two seasons too long (which isn't an uncommon opinion, to be fair), 7 seasons is far longer than most BBC shows last.

And, as another poster noted, I would argue that a lot of people think the BBC version of Sherlock has definitely gone on way too long.

I think British TV has actually started taking influence from American TV over the past decade or so (or at least realized that Americans are watching and have started to cater to those audiences). Downton Abbey I feel also similarly went on probably a couple series too many.

Wow, you mention the one time where a US show manages to give a character depth while the British version utterly fails at that and instead decides to keep it alive with cheap gimmicks.

Which of the GP's examples are you talking about? You could be agreeing with them on House of Cards or disagreeing with Elementary/Sherlock or The Office - it's not clear which.

Sherlock/Elementary I think? Personally I find Elementary way to gimmicky/tacky but happy to disagree.

Sorry, Sherlock/Elementary.

I'd argue the same with House of Cards; the longer format was enjoyable at first but it definitely went on too long, and I think lost some focus along the way.

I think it is the different set of Interest that sets them apart.

BBC being funded by tax payer's money compared to US for profits company where they have incentive to not cut off their series with many viewers?

Majority of BBC funding is from TV licensing, which should be considered a separate thing from tax payer funded.