Thinking out loud really.
Parliamentary systems are generally more stable and more populist-friendly than Presidential/Congressional systems.
Also, the US Judiciary is a clusterfuck. Alternately the strongest and weakest branch depending on how daring the chief executive is feeling at a given moment. As much as America needs a parliamentary system, it needs judicial reform to match.
They do, it’s impeachment, it works about as well as a non-confidence vote.
A successful no confidence vote in the UK triggers an election at the earliest opportunity
Party leader resigns and their next party leader takes over and nothing changes most time. A no confidence election doesn’t happen if they resign, there’s ways around it.
No confidence votes are a referendum that forces a new vote. Impeachment is done by representatives and kicks off a process that gets blocked by the senate and results in no change, ever.
Impeachment is the US legislative form of this, but it almost never happens because getting the two party system to engage it in both the house and senate is too high of a task.
That being said, be careful what you wish for: https://en.wikipedia.org/wiki/No-confidence_motion_against_Imran_Khan
Parliamentary can be better, but there’s always the chance it backfires and it becomes a massive bribery scheme, which would be even worse in the US because lobbying in the US is legal. You’d just end up in a situation where highest bidder can change between parties on a whim with reduced repercussion from voters.
All they really need to do is reset the senate into proportional representation with a constitutional amendment because state’s rights stopped existing decades ago, especially after SCOTUS torpedoed basically all the individual rights asserted by previous cases, including limits on lobbying.