I totally agree with all of that, and implicit within it is that Bitcoin is heading towards usefulness for large sums mainly. The pricing structure for block fees is based on what satoshis were worth years ago and I see no sign of any incentive for any solution that would lead to lower fees. What would create such an incentive is some upstart focused on making mining more affordable to create more competition. Currently supply and demand favours the largest miners. So, yes, exactly as you say, technical advances. But if they are market driven as they surely have to be then more accessible mining technology has to be the way. 

 I've thought about the possibility that once the block rewards get lower the mining could transitions back to smaller communities and groups, but we've already had blocks where the fees were more than the reward... so prob not. Maybe each community that runs a mint also runs some miners. I could see it making sense IF the fees are lower and that way the mining stays active and you have people with incentives to keep things working well. I guess we'll just have to see how the financials work out over time. 

 Supply and demand... When bitmain need to expand their model and realise efficiency and affordable are the way to go or else leave the door open for competition. Christ I wish I hadn't slept through my electronics lectures.