Moore's law. Bitcoin's blockchain we can assume to be roughly double what it's current size is in a few more years time, and of course that will be determined by block size changes/capacity as well but we're essentially looking at a blockchain no matter how you look at it under 1 Terabyte even in 8 more years time. 1 Terabyte in eight more years should only cost roughly the price of a little cheap flash drive at that time.
But that does not take into account bandwidth speed and costs. The larger the blockchain becomes, the harder for Bitcoin users to run a full node, opening the network more to centralization.
I tried to run one at home this year but everytime I try I always get discouraged by how large the blockchain is and how long it takes to download all of it.
That's true. Normal user does not get enough incentive to run a full node, even if storage becomes cheaper. That's why some people against too large block size.
Maybe it could also resolved technically, like compact early local blocks, records compact hash and unspend transactions only?