It is definitely possible. I started a new game on my boyfriend's ipod and one of my peeps mastered his job at the age of 37 (could have been earlier but I just opened the game this morning). It's the end of the second day and I have 25k saved up.
When you are not actively playing be sure to completely close the game (for me, I exit the game, double click the home button, press and hold on an icon until it shakes and then close VF2). I find that they earn a LOT faster this way. Give it a try and see if it does anything. I also make sure to praise them only for working and exercising. If they are doing something else, I drop them back to working.
One thing I noticed, the more career upgrades you have the longer it takes for them to complete their work cycle because they play with every single item you purchased. It may cause a greater increase in their job leveling, but it takes longer so I'm not sure if it really helps seeing that my first generation was able to master his job at 37 which is roughly the same as my other game with more career upgrades.
When you are super tight on money, just sell your furniture. You only need a couch. If you bought your items at sale price, you make back everything you spent. If you paid full price, then you only get back half of what you spent.
Hope it helps. Good luck and don't give up