I picked up a Kindle Paperwhite...oh, a year or so ago, I think. Currently have about 150 or so books on it. Couple weeks ago, I started organizing them into folders, because the KPW's navigation software is horribly limited. Not entirely done, but no matter what...finding what I want won't be all that easy. And I've been heavily series-oriented; about 35 of em are in 2 series/collections.
And that's content in the hundreds. Not 10,000 songs and 2,000 videos. Space isn't necessarily the issue; effective access is.
Another aspect...backup. Are you really going to trust 10+ years of video and music collection to your SSD alone? Would you rather have one massive 128 TB internal drive...or something like a 4 TB drive, with an external RAID unit hosting 5 more? Which, BTW, is gonna be a tiny fraction of the price, no matter how much cost per terabyte drops.
Data centers justify huge drives because they save on power and air conditioning costs...savings which are trivial when talking 1 or 2 drives, but add up if you can replace 10,000 drives with 1250.