This "hobbyist" will just have to start shopping on torrents if it ends up i'm supposed to pay £150 for an OS.
No - the thief will continue to use the torrent sites.
There will always be scum out there who feel that they shouldn't have to pay.
Cost is usually a great argument - as I've said before, just because you can't afford something doesn't give you the right to be a thief.
If you just don't think it's worth the money then don't use it - if you use it then obviously it is worth the money.
Don't tar all "hobbyists" with the same brush.
Many of them are not thieving scum.