ASIC chips can never keep up with the logarithmic increase in power required to solve the algorithms.
Do you realise that mining difficulty is a result of increased hashrate and not the other way around? Miners don't have to keep up with the difficulty, the difficulty keeps up with the miners. The only reason the power required increases is because the hashrate increases. When we run up against the physical limit and Moore's Law stops applying there won't be new generations of ASICs, so the hashrate will stop increasing exponentially, and so the difficulty will stop increasing exponentially. You have the whole causality of the situation backwards.
So why have the number of miners fallen from hundreds of people like Bob in a backroom with a PC to a few huge companies (in China) with farms of machinery? Because the hashrate has gone up so much. But why has the hashrate gone up so much? .... Chicken or egg which is first? To be honest, it does not matter, only that Bitcoin is reliant on a few (almost getting centralised) Chinese farms. We, the community, have little input, in fact zero.
First of all that's not true, the hash rate has gone up because the amount of miners has gone up, because with each generations PCs/ASICs get better. I don't think the number of miners has decreased, yes the chinese may be a big % of the miners but with this price grow i can say for sure without looking at charts that many have turned their miners back on. You just changing the words so it always looks in your favor.
I dare to say that it's logical that if something becomes productive then many will start aiming for it, thats the only reason because Bob cannot mine with his PC anymore, yet if Bob used to mine with his PC and now is bitching it's just greed since he already has a huge amount of coins.