> best handled by the people who have dedicated their lives to becoming politicians, the same way that getting your house wired is probably best done by someone who spent their life becoming an electrician
Being an electrician makes you good at wiring houses in ways that work, that pass code inspections, and that don't burn down. The feedback loop isn't perfect (you're likely to succeed for a while if you produce flawed work fast that looks good enough to your boss), but it's at least feeding back in the right direction.
Being a politician makes you good at different things - fundraising, advertising, speeches, getting your name in the news - which are totally unrelated or even opposed to creating and executing legislation that is good for society. Sortition says that this relationship is so bad that the outcome under a lottery (the 50th percentile, eliminating the 49% of the population who would be better than average at the job) results in better outcomes than career politicians.
This is an incredibly limited understanding of what "politics" entails and also seems to be primarily informed by the outcome of the US political system.
Most politicians outside the narrow world of US national (or otherwise high-profile) politics have very little contact with fundraising or advertising and few will ever give a speech to more than a handful of people. I.e. most parliamentarian democracies are chuck full of politicians that even most of their direct constituents couldn't name with a gun to their heads, even at the national level.
In these kind of systems, actual expertise is really important and political parties will cultivate subject-matter experts and provide them with secure seats or list positions without necessarily putting them into front-row politics. It's just the smart thing to do, if you actually want to have any effect after winning an election.