This is always a problem at the client end of the equation - our data is hosted on AWS and is served via a professional content download network. Typical download rates for customers are always in the 20-30mb/s with many customers getting much higher.
When a customer asks us to check we always get instantly around 50mb/s running the installer and we are neither local to the servers or on some preferential download from the servers.
When we investigate issues like this with customers they are always caused by the customers own service provider directly throttling the data we are sending.
The best solution is to use a VPN to hide the data - this is not always successful as internet providers have got very good at dealing with VPN traffic and still managing to control data rates but in many cases it can solve the problem.
Sadly net neutrality was lost long ago and as such internet service providers can choose to throttle whatever data they wish and we have no control over what they choose to throttle or not throttle.