I remember reading this here the other day I think, and it was at a 1MB blocksize rate.... I would guess that in 4 years maybe the blockchain has been increased, at least doubled.
Anyway, let's imagine it doesnt, and we stay at 1MB.... what do you think the price for 700GB will be in 4 years? If things don't change much, it means running a node will take almost an entire HD (let's say the usual HD size is 1TB).
What happens once the size goes beyond 1TB, or beyond the biggest HD? what happens when you can't fit the blocksize in a regular HDs? Can you run 3/4 of the blockchain then the remaining 1/4 part in another HD?
There is no reason for the core developers to do that.
700gb is x700000 then the current block size, even if the whole world are going to use bitcoins at a daily basis we won't need such a block size.
Anyway, such a block size would hurt the community, as machines who stores the whole blockchain will need to have a massive built-in memory, which is almost impossible, and will make running a node alot harder and much more expensive then it used to be.