OK, so the first thing to know is that UK politics is all about waiting for the current party to mess up giving the other party a decade or so in power, until they too mess up and the cycle repeats itself.
Gordon Brown was in power, along comes the 2008 Global Financial Crisis, voters notice that in their quality of life and don't like it. They don't want to re-elect Brown, and that means electing Cameron instead.
Then the conservatives get to hang on to power for a few decades until they have an economic crisis of their own thanks to a disastrous mini-budget that sends mortgage costs skyrocketing. A load of sleaze, corruption, lockdown parties etc add nails to the coffin.
Secondly, the conservative party is united by a determination to win power, rather than any particular ideological stance.
That's in contrast to parties like the Liberal Democrats, a party entirely comprised of people who've made peace with the fact they're never going to hold power. And the Labour party has many members who passionately support Corbyn despite his inability to win elections, and are lukewarm about Starmer who isn't ideologically pure enough.
This gives the conservatives a great deal of flexibility in adapting to public sentiment. When Cameron won election with a socially liberal approach, environmentalist policies and legalising gay marriage, the party would back that. When there's a change in the political winds and Sunak decides that 'ending the war on motorists' seems like a vote winner, the party's more than happy to back that too.
Thirdly the conservatives have some popular policies - for example, the Conservatives have had three female prime ministers, while the Labour party hasn't even had a female leader, let alone a PM. And 50% of the electorate are women.
The conservatives they'vehave largely avoided any expensive Blair-style foreign wars. The UK conservatives also differ from US republicans a great deal: UK conservatives don't give a shit about religion, abortion, or guns.
They also have a reputation as a party that would sooner cut government spending than increase taxes - that's popular with a lot of people. Sure, maybe they'll have the taxpayer foot bethe bill for dredging their castle's moat, or they'll buy a few hundred million pounds worth of defective PPE from their child's company - but they won't raise taxes to pay for it.