It is worth it if you don't take a loan and dump all your money into it as a full time job. If you have a full time job and the cash to spend just do this as a hobby to make extra cash it is still worth it. The huge miners is what hurts the little guys anyways.
Actually it is a bit more complicated. First you should invest into hardware equipment. It's not only GPU, but HDD, PSU, memory, motherboard.
After that you should pay for electricity. Now it is about 1/3 of income in case of efficient GPU.
From other 2/3 income you may want recoup you investment cost.
It is not obviously becouse after 3 years your GPU will be obsolete for sure.