I am new to this so might be a dumb question. I am wondering if all bitcoins will be mined? I have read that its not worth mining anymore for people with standard computers because it's too hard, better mine litecoins. What happens when it becomes even harder? In six months when the difficulty is even harder it may not be worth all the electricity keeping the stuff running.
Is it even worth getting the mining computers for $5k+ anymore?
The system is continually rebalancing. If it becomes too "hard" some miners will quit (those with the highest cost and least efficient gear), when they do difficulty will fall and remaining miners will earn more. Of course that lower difficulty will bring in new miners who will drive it back up.
There can never be a scenario where nobody mines because it is too hard. If less people (or hashpower) is mining then difficulty will get easier not harder.