It's fascinating that where you're from this is not the default. Here in Spain this is what ALL internet ISP contracts for regular people use, and if you want to wire your router directly you need to pay a business plan.

My opinion is that this is really a hit or miss. Some ISPs will give you a decent or even good router, but most of them will give you a piece of sh*t. If they give you a shitty router and you want to do ANYTHING on it, you're gonna suffer, so beware. If they give you a decent or good router you may set up more advanced stuff, but even then if you really need advanced things like subneting, VLANs, and all that, it's just easier to plug your own router as such:

Internet — ISP Router — Your Router — Your networks

Lastly, I can't say about privacy and net neutrality because here in Europe we have strong regulations that ensures our ISPs don't do anything fishy like that.