Could video streaming sites be throttled?

[strideram 11]

I tend to stream animes/tv shows. The hosts for these shows tend to be mp4upload.com, videonest, auengine, 4streaming.net etc. Point being, there are multiple such hosts.

 

I have a 4Mbps connection. Irrespective of whether I am connected to the VPN or not, I get between 1-2 Mbps speeds when streaming. If I instead try streaming from vimeo.com or youtube.com, i get proper 4Mbps speeds. Initially I thought my local ISP was throttling them, but then the VPN should be able to help me bypass the throttling right?

 

There is also the remote possibility that these hosts are facing bandwidth issues at the same time. I would like to paste a few video urls (anime episode links for each of the mentioned hosts) hoping to gather feedback on whether other users are also facing speed issues, but I am not sure whether its allowed in this forum?