Have many pilots had a career with just the PPL + FI(A)?
A career? Well, if you call flying part-time at a local flying club during the weekends a career, then yes. With a PPL you can not talk about a career, even if you hold a FI with it. As already mentioned before, if you're seriously thinking of a career in aviation, then don't waste your time (and money) with the CPL theory, since your options are quite limited as compared to the ATP ticket. Do some research, not only on the Internet, go out and visit some flightschools and talk to the peolpe there. And secondly, I've noticed you're quite young, meaning you'll never know what direction you might be heading to in the future and what opportunities might arise, which require you having the ATP (theory). Perhaps there might be the opportunity of piloting an A380? Life is full of surprises, you never know! Which I'm trying to say is, don't limit yourself at such an early stage in your life! If money is an issue, then I'd say wait a few years, safe some money and then go for it! Anyway good luck!