Mining with cpu lasted for like 2-3 years.
There was official letter from Satoshi asking people not to use GPU mining so that more people can participate.
Of course there were people who ignored this and mined with GPUs anyway but it was hard because there was no apps for this so you had to write the programs yourself.
You can't really mine faster than ASICs as they are the most optimized hardware currently available. By definition ASIC is optimized completely only for making bitcoins. There is no higher class of hardware above it. You can only make a faster ASIC.
Do you notice Halong mining, which improve efficiency a lot.
When BTC price is low, people does not invest money to design the chips.
And when people designed it, alway mining themselves, and sell to you several months later.
I heard this rumors a long time ago:)