In breif--Mining will become cheaper and cheaper, Asics will become more efficient, People will use solar, wind or whatever, you will see. If BTC needs to change it will, otherwise people will work around it. Money talks here.
You may like this discussion below, from someone similar to yourself advertising BitsharesX as they want people to throw money into it like they have.
https://bitcointalksearch.org/topic/its-about-time-to-turn-off-pow-mining-770591I remember earlier this year when there where around 300 coins and Infinitecoin was 7th not because it was anything special, simply because it had billions of coins and a very tiny amount worth.
My not so technical opinion ( By the way I do not believe the consensus algorithm alone is holding BTC back, as it is giving it another layer of security so its a trade off many people seem to prefer. $470USD per coin from something that bootstrapped itself from nothing is not something to laugh about, lets see what the next 5 yrs bring us)
Usually people tend to move towards the money and if they have enough invested into it there goal is to keep it working, Gavin is very well aware of POS and DPOS and I am betting they have already discussed it numerous times.
As you said -- If the amount of Miners and the amount of buyers are causing the price to halt where it is now because of the equal pressure either-way then what your saying is a shift in either way will send the coin up or down. Hmmm I don't think this is the only thing relating to the price, but it definitely is a factor. But I believe when the rewards drop in 1.5 years this will shift the balance and if what your saying is still true the price should keep rising from then on.
In regards to Decentralization, I do not believe there will be 1 warehouse full of mining equipment I believe there will be hundreds of independent data centers mining away with Solar, or wind generated power maybe even asics that VERY little power , they will also become cheaper bringing more people into the game. But I am also curious to see what the future holds, but money talks and so far BTC is the big brother with MANY shareholders ,very smart savy investors and very smart tech heads, if BTC needs to change it will, and if it doesn't it wont. Resources will just get cheaper, Solar, wind, as well as very efficient asics, i believe asic power may hit a plateau and the energy to run the asic will just become more and more efficient