That would defeat absolutely nothing. Once thoroughly verified, old versions of the blockchain NEVER change, so that would be very stupid to insist that the only way to get the whole blockchain is to download it all through slow network connections and very slow servers, knowing also that the blockchain tends to grow faster with time; what a stupid waste of network bandwidth and time! Yes, one can of course use a thin client instead but that was not the point of my post.

As I understand it, that is exactly what happens everytime people transact. Anything (fiat, bitcoin, even hardware, anything deemed of value) paid to a third party (a bank, an exchange, an internet hardware reseller, etc.) is a zero-interest loan you make until you receive your stuff (bank account interest, bought hardware, etc.). Everytime you pay someone, you're giving them the opportunity to spend your money before they give you your stuff, and so introduce liquidity/solvency risks best illustrated by ponzi scheme failures. That is credit creation, and it is enabled just by the consumer spending money and waiting for his stuff. That's why being your own bank/custodian (= being in possession of your money/stuff) a maximum of the time is the antidote -- avoiding third parties by using decentralized exchanges as much as possible implies being your own bank/custodian. But, as already said, that also automatically transfers more responsibility directly on consumers.

Trying to be your own bank/custodian means you're trying to reduce the opportunities for third parties to profit from your money/stuff while it is in their systems by 1. getting rid of useless third-parties and 2. reducing delays in transaction settlement/clearing so that your money/stuff is in the third party systems a minimum of the time. Having zero delay is impossible for many kinds of transactions (or even not wanted, e.g. bitcoin mixing), but with bitcoin we can certainly do way better than the huge delays built into the fiat banking system!

Interesting device (that actually costs $50, not $20, for the basic version), but the router still needs to download the whole blockchain and you need a spare disk, so that will not solve the download time problem. If demand is sufficient, a better solution would be flash memory/usb flash drive(s) sold with the initial blockchain already written on them, and a full node software update to allow it to directly read blocks from the flash media, in addition to the newer blocks on the hard disk. Flash media is ideal for that usage because it's cheap, has standard capacities similar to blockchain size, is efficient with random read-only access, and the blockchain copy can easily be updated from time to time with new blocks accumulated on the hard disk. That's also better for your hard disk health and availability.