> And? She was removed. In most other political systems, it is not possible to remove someone in her position because we have a parliamentary, not presidential, system.
Still allowed to criticise the system for allowing her to gain power. No brownie points for the fact that her party recognised she was such a disaster they would cease to be a meaningful political force at the next election, and therefore made it clear that she should resign. This can easily be replicated in other systems. They don't need to have an official way to force leaders out: she, officially, resigned.
> But Johnson, for all his faults, was the right man at the right time, and left when he was supposed to.
Oh god no, he was a walking disaster area well before he became the uncontested replacement for May. He was fundamentally unfit for office and shouldn't have even been allowed to stand as a Tory candidate MP given his pathological incomprehension of the concept of truth as something deeper than an ad hominem attack. Allowing him to be PM has almost certainly undermined UK national security given his complete lack of restraint or self control in either lust or money.
Only reason he won the election is because Corbyn was so unappealing that even the parliamentary Labour party overwhelming rejected him (what was it, all MPs not in the shadow cabinet?), which is exactly him sticking around for years in the way that you're saying doesn't happen in the UK.
But why did he stick around when the Tory MPs could kick out their leaders? Because Labour's leadership contest allowed candidates rejected by the party to be on the ballot, while the Tories (do they still change their method with each leader or was that just the Blair years?) don't.
> And we didn't get a Brown situation (you may have forgotten that Brown also polled under the Lib Dems in the run-up to 2010, Corbyn was leader for how long...and he actually polled under the Lib Dems too in 2019).
That was unusually high LibDem support of 29% instead of the usual 10-15%, not a spectacular catastrophic nose-dive by Brown.
Corbyn should've gone after the first election or the leadership contest. That he didn't proves the UK being parliamentary didn't help.