The solution is that politicians need to be held to a much higher standard than the letter of the law, by their voters. It boggles my mind how many politicians have such obvious conflicts of interest that manage to retain approval of their constituents.
Feel free to disagree with that. I stand by my point on account of the lack of transparency (e.g. no obligation to make ancillary income public) and the legality of the "Revolving Door"-effect.
Government officials in Germany are free to leave office for private enterprise with no restrictions. Public officers have to report lobbying jobs to their former office for 5 years, but the worst that can happen if they don't is loosing their pension.
The latter is not much of a problem, though, if the new employer just pays well enough...
This leads to CFOs of DAX companies becoming government officials in the ministry of finance; public officers serving in the ministry for radiation protection who dealt with interim storage facilities to leave office for (nuclear-) energy companies, and so on.
Holding politicians to higher standards than the law is delusional. Politicians are humans, too. None of them are Jesus Christ incarnate and none of them should be either, because in a democracy they should represent The People, not some Utopian ideal.
> It boggles my mind how many politicians have such obvious conflicts of interest that manage to retain approval of their constituents.
That's because in Germany, nobody knows that there even is a conflict of interests, because politicians aren't obligated to make additional income public.
A reasonable first step would be to make that mandatory (you don't even have to disclose exact sums of money, but it helps knowing that your representative has a paid seat in some board of directors on the side).
That is an assumption on your part. In the absence of thorough investigations that would condemn or exonerate them, it is difficult to say. Of course, it would be very twisted to say that the lack of investigations is proof of real corruption. Still, it should also not be taken as prrof of no corruption.
This is why legislation and regulations need to change, because that's way easier than trying to change people.
If you don't like the rules of the game, demand to change the rules instead of shouting "You're all cheaters!" and stop there. That's just cheap and not helpful at all.