Each of them may only increase by a factor of 5 (example number), but if you combine them you could get 25x improvement. Obviously it's not enough to billion users, but i'd take small improvement over nothing. Besides, IMO it's just matter of time before block size is increased and it'll be faster if Bitcoin community want higher transaction throughput.
The point of bitcoin is decentralisation, and throughput scales only linearly with block size (obviously).
As block size limit is increased, the number of node operators must decrease - i.e. everyone running a node on a Raspberry Pi and 1TB external hard drive will have to buy 10 or 100x the storage.
I understand cost of increasing block size. But don't forget growth of hardware processing power and internet speed growth either.
Actually it's a bit of a catch 22. If we:
a) keep the block size the same, this necessitates the use of Bitcoin banks. If you are storing all your funds in a Bitcoin bank, then running your own node is pointless, because the bank has ultimate control over your BTC.
b) increase the block size 100x say, this would permit individuals to continue transacting on-chain in a hyperbitcoinised world, but it would also drastically increase the hardware requirement to run your own node, making it much more difficult for the average person to run their own node.
I think ultimately Bitcoin banks are the future. The vast majority of people will never run their own node, regardless of the barrier to entry. Sure, you will have to trust the bank with your coins, but I think that is fine. If a bitcoin bank tries to run off with 100,000 customer's coins, there are not many places in the world they would be able to hide from the 100,000 strong angry mob that would form.
Rather than bank (or other custodial service), people could use various off-chain (such as LN) or side-chain (such as RSK or Liquid) solution.