A plausible view of UK politics over recent decades is that we aren’t supposed to take it too seriously. For example, only relatively small numbers of people take the major UK political parties seriously enough to join. Even 0.5% of voters would be a substantial party membership, so what are the parties for?
Perhaps political parties project an unserious view of democratic politics because voters don’t take them seriously enough to become members. The symbiosis of political doom we might call it –
You don’t take us seriously so we don’t take you seriously.
Maybe it was inevitable that what we end up with is mostly political theatre, attracting actor politicians prepared to cater for that. Over time, voters tire of the performance but politicians know this is their destiny. It’s a gamble they have chosen and what voters voted for.
Ruling political parties expect to be booed off the stage eventually, but there are compensations. Politicians have the prestige of being an MP or Minister, plus salary, expenses, social contacts and further opportunities - compensations their talents would not usually have attracted beyond politics.
Inevitably the State tends to take advantage of unserious political parties. The complexity of government, the brief tenure of Ministers, the lack of experience all allow the State to ensure that its internal functionaries are not too heavily damaged by failure. Politicians end up damaged instead, they absorb the damage, shift the blame and move on if it won't be shifted. Political parties have become the political armour of the State. Voters let it happen.