All political decisions in western democracies have a hard limit of a four year time horizon. Sure, there are times when collective decisions can be made with decades of planning - but only if they can fall through the increasingly narrow gaps between left/right politics.
Don't get me wrong, it's still better than any alternative I've seen anywhere, but it has its weaknesses.
5 years in the UK, though it's been a long time since there was a change in power between parties without a 10+ year stint in office first.
The last year you don’t want to piss off the voters so you have to be very sparse in getting anything done, so the last year in the election run up is spent pandering to as many people as possible rather than actually doing any of the real work.
Even if in the end you get multiple terms in office, you were never guaranteed re-election, so you were forced to make short term plans regardless (to stop the other lot getting in instead).
Not sure I follow your point.
Elections happen every X years whether you win them or not. The job of a politician is to pander to the electorate, not take action.