One good way to proceed faster in the later stages of the game (without using an auto-clicker) is to try getting the OS upgrades ASAP and then formatting the system. OS upgrades give a huge boost to income while being permanent upgrades (You can upgrade to the OS you were at free of cost after a format).
How to make money in LtF3:
1) Cash in your bonus points for interest and money boosters
2) Sell everything you have (Body, Boosters, etc)
3) Start your day for instant cash doing nothing
I actually have an idea of this awesome game. It is that in the hardest difficulty, there will be a main road having random cars. They will create the traffic when cars need to pass through the road. I would also like having wider roads which I think will take time.