You're right, although I'm not sure if people necessarily go to their ISP or to the cheapest host possible.
Most of the time, in my experience at least, someone that wants cheap hosting and is using something like .NET or Python will Google "cheap python hosting" and see what is cheapest/recommended.
PHP tends to be the outlier, because it's absolutely everywhere, but I think the web has matured to a point where people will look for specific hosting for their choice of tech. Hell, back in my freelancing days when I used to rebuild broken WP builds, most people that weren't given hosting by their client chose it from looking up "cheap wordpress hosts".
When time came to replace my XML/XSLT based website by something else, just to get up with the times, I resisted to touch PHP, but in the end having it at my ISP versus the trouble of using something else won.
Nowadays I am able to use PHP 7.x, so I just keep using it there, and suggesting it for the less tech savy friends that want some kind of dynamic website.
Because while I do build sites in Java and .NET, I do accept that they aren´t that easy to set up at most ISPs, and cloud based one click solutions tend to be more expensive.
Most of the time, in my experience at least, someone that wants cheap hosting and is using something like .NET or Python will Google "cheap python hosting" and see what is cheapest/recommended.
PHP tends to be the outlier, because it's absolutely everywhere, but I think the web has matured to a point where people will look for specific hosting for their choice of tech. Hell, back in my freelancing days when I used to rebuild broken WP builds, most people that weren't given hosting by their client chose it from looking up "cheap wordpress hosts".