The people who pointed out that none of the moving parts of DigiD should have been outsourced were ignored until the tide shifted this year.
I'm honestly surprised the government decided to intervene. The usual method is to keep on believing in the signed piece of paper until the shit hits the fan (like with the Fyra high speed trains) — never mind that the US (where the buyer is from) is not likely to give a toss about those pieces of paper if they need something from our data.
So you have to weigh the risks of outsourcing to the risk of the whole thing becoming very late and very expensive. The risks around outsourcing are something further down the line, the risks of everything becoming expensive and late are something that will give the responsible politician a headache now.
IT is hardly something we need to do occasionally, so build up a department that can do it (not just write up huge reports about what it should do and outsource, like Logius) and invest in the people that will work there (retaining them as much as possible). Give a big middle finger to consultants, and listen to the tech experts. Build boring stuff that works instead of a new app every month.
It's not impossible in theory, and cheaper in the long run. It's impossible because asshats who would actually benefit from left and centre politics keep voting right-wing parties in to power.