4Mb is only a theoretically possible block size, we're never getting there in practice.
I own an external 2GB SSD drive. I'm not some crazy geek, this is a consumer product.
It is theoretically guaranteed to be able to contain the blockchain for another 10 years.
In 10 years 2GB SSD drives will probably cost what 128GB USB flash drives cost today.
That said, there's no reason for any pleb to actually download the entire blockchain and there's literally nothing wrong with using SPV wallets, so why would it matter. I stopped using Bitcoin Core software in 2016 because I didn't wanna melt my CPU with all the block verifications - so ordinary users are already NOT using bitcoin core, opting for SPV instead.
Completely agree about the SPV alternative. To add to the topic, there is a great video by Peter Rizun who explains how it works and covers the potential downsides -
part 1 and
part 2.
TL;DR: In short, security on SPV is fine, there's a problem with anonymity that needs to be addressed (and he has a plan on how to improve it). But if you're so desperate to remain untraceable, then you should probably invest in a modern machine instead of a 10 year old laptop (that's my opinion, not his).