That will depend on your provider. Some ISP have good connectivity with some networks, some have shit. It doesn't matter what YOUR connectivity to YOUR ISP is, it matters what the ISP has.
In the old days (read 1999), data flowed where it could and where there was capacity. That's no longer true: data flows where your ISP pays (or, depending, where the other guy's ISP pays). Here, for instance, people can switch ISPs, keep the same landline connected to the same DSLAM, and have their Youtube speed go from stuttering at 360p to lightning fast buffering at 1080p. One ISP has decided that the network necessary to connect to Google's infra was asking too much, and doesn't pay; the others have caved in and pay.
Elaborating: At home, I've got basic cable, with about 15Mbit/s. I watch 1080p or "native" videos no problem. At work, I have 100Mbits/s but I'm borderline with Youtube at anything beyond 480p. Reason? My home network is a consumer network, access to Youtube was important. My work ISP is an academic/research ISP; youtubers aren't their priority.
(oh, and I got lucky with Valve's network; my laptop upgrades Steam stuff at 5 or 6 Mbyte/s at work, but caps just below 2Mbyte at home).