GO INDIE FULL TIME!!! :D that might help, maybe. :D I'm 26 and still not giving up :D I'm confident that I'll become a game dev full time pro indie !!! (Even with wife and children :D) Bro, honestly, don't give up! You can do it put your brainz into it :), visit dailywtf and failblog to get some mental garbage collection :D

You forgot the major reason for not testing "properly"... no time! I mean seriously the understanding of a system depends on so many factors that its impossible to figure out whether its understood or not. IMO the reason for too many bugs is the count of young developers and the bug count at this rate is awesome and it should stay like this! We always have to consider that all of us were noobs once(I'm still, kinda) and that there will always be "new Guys" in almost every development project in this world :D and that is perfectly fine :D