I believe the most of member here hasnt skill of developing or creating if they had why would they do signatures to get some bucks when they can make thousands;Most member here has no special skills they do signatures,and invest at bitcoin or altcoin market hoping to get a good reward.
No offense, but it sounds like you are referring yourself. It is because you are wearing a paid signature as well. I'm good at multitasking, and I have a lot of free time when I'm at work and home. That is why I am online in Bitcointalk most of the time.
0.5 btc is not a big deal I guess, If you have a multi skills then you can make it easily in one month's time, it depends on an individual and the skills that he holds.
One month is a lot i would say, for a multi tasking person who has so much free time like the mate said above.
Someone with some unique skills and experience and some free time can make that amount even less then a month.
All he needs to do is to work in his free time and concentrate on his work, and he will get what he wants in no time i guess.