Storage drives are pretty cheap. If someone can afford $50 a year for a node, they could afford $60. Storage is only getting cheaper as we move forward.
It is not about storage. It is about verification time. If you can download 1 GB/s, but you can verify 1 MB/s, then verification is your bottleneck, not storage. Who cares, that you can download the whole blockchain quite fast? Verification time is more important. If you can verify 1 MB/s, then it is fine, because when you verify 600 blocks, then in the same time, one new block is produced.
However, if you have 600 MB blocks, and your verification time is still 1 MB/s, then the time to verify new block is close to the time of making a new block. And then, you have a problem, because if your ratio of verification time to the new block time is too high, then you can reach the point, when you never verify new blocks, even if all of them will be downloaded on your disk.
And yes, I know we will not jump from 1 MB or 4 MB into 600 MB. But every increase means that verification time will be increased.