I absolutely agree that you can have a good career without having a degree (or a degree from the right school), but you will have a very tough time getting beyond a certain threshold. I understand it's very obvious in France for upper management and public/political higher positions that it's not merit-based. The same is true for most countries, with varying degrees of impact and obviousness.

But if you're not going for that threshold, you'll likely not run into issues. And if you're in niche-careers, it's probably true as well.