Hi Dave
they are not cheap hosting they are around $250 a year, the issue comes from cPanel turing this feature of by default and have told all hosting companies to do so.
I spun up a VPS server the other day and do an install of cPanel and yep there it was turned off by default.
here is an excerpt from the ticket from a large hosting company here in Australia
We have checked and confirmed with our System Administrators that the PHP Functions (show_source, system, shell_exec, passthru, exec, popen, proc_open, allow_url_fopen, pcntl_exe) are all disabled on all Shared Hosting servers. This change was made due to potential vulnerabilities being exploitable using those functions. For the same reason, the decision was not made public and was on the advice from WHM/cPanel.
Thanks
Craig
KC Media Solutions
www.kcmedia.biz