I think the forthcoming EASA rules will allow PPL FIs to teach what is now effectively the NPPL. So the scope of clients will be quite limited.
There are plenty of FIs around at the moment with CPL/IRs, and granted not a lot of hrs, but at least they have passed some very difficult flight tests.
Another issue is that to pass an FI course in the UK your SEP flying needs to be 'tip top,' and unless you have a lot of hrs, you are better spending the money on a CPL to get to the correct standard.