I'm surprised people don't mention about Compact block when we're talking about block propagation, block size and scaling. But it's not applied for nodes that just went online though
1. Block propagation is very fast as compact block have very small size (AFAIK about 10-30KB for 1MB block size)
2. Block verification time is fast as all transaction inside block already confirmed when it's broadcasted
3. AFAIK both block propagation and verification time should take less than 20 second (based on a presentation/conference video i've seen few years ago)
Regardless, few things such as Initial sync is serious concern as it took few days to few weeks (depending on internet speed, storage speed, etc.)
the main irritation about the initial block sync is not actually "cost".. but the time.
and when actually poking deeper at the irritations the main rebuttal i hear again is not cost. but the fact that people cannot see their 'final balance' until the syncing is complete. which means they cant really easily see if imported their wallet correctly or even make a transaction until the syncing is complete.
this can easily be remedied.
imagine getting to see a 'unverified' balance within seconds of opening your node for the first time. via SPV methods(grab a rlatively fresh UTXO set from peers). and thus using a fresh UTXO set, then able to know you have imported the correct wallet by seeing aatleast a unverified balance and also then able to make transactions.. then the whole blockchain syncing becomes a background issue rather than a stare at the screen waiting issue
its like online gaming/phone apps these days. get to play with a small single level demo of a game whilst the whole game downloads in the background. people can the be instantly entertained and not be as concerned about waiting for the game to download, as that main download is treated as a background issue.
lastly the fee being more than a few hours of minimum wage labour for MILLIONS of people in third world countries deters more people than the cost of a hard drive or internet access