2. Adaption of other technology such as Signature Aggression, MAST, etc. which reduce transaction/script size and allowing more transaction fit into a block (assuming transaction fees remains same)
I will take a look to understand MAST but what exactly meant by "Signature Aggression" ? Are you referring to development in signature like Segwit or Schnorr.
There are several assumptions to be made if you assume that:
1. The efficiency of ASICs and electricity fees remain constant from now till then.
2. The number of transactions per block and the price of Bitcoin remains constant.
Agreed , I certainly overlooked "The number of transactions per block" can be increased and I think we need to find new ways to increase transaction in block as we diminish the block rewards.
If efficient ASIC also means cheap ASIC (miners cost for hardware setup is reduced) then it is a plus point.
I do not think electricity cost will go down, on a contrary it is expected to rise to make mining more costly.
Price of Bitcoin is a two edge sword, miner will be happy to get more money and it will be act as incentive to them but for a bitcoin user it will mean high transaction cost and there will no incentive for user to pay premium for a transaction when it can be done for free if both peer have account on same bank or bank will be doing cheaper transaction than
BTC. If there is no end user to do transaction and no block rewards (or diminished blocked rewards) then what will miner earn. Actually high price of
BTC can backfire also.
BTC is still young and needs time to mature. Within 9 yrs of existence there has been numerous development in the btc space which makes them increasingly convincing to use along with the fiat money.
In technology field I will say 9 year are not considered as young but like "Grandpa" because sometimes technology become obsolete within a decade.
Continuous development and solving problem can give you the userbase otherwise userbase shifts rapidly to a better technology.