Whether you're using hardware RAID or not you still need a hardware storage controller of some type which accepts the new disks you can buy and works with the NAS. What they are saying is eventually that'll be more $ and time than just migrating off the system would be. From ENIAC to now could fit in one lifespan, would you still be maintaining a home floppy drive backup system in the 2040s or just save the time and effort with a migration?

sure, you can always move the old storage mechanism to something new if it is too cumbersome.

why still back up floppies if you could just move the data to a single dvd, or throw is on the SAN?

RAID is just algorithms, the actual transport doesn't matter (i.e. spinning platter and solid state both use SATA connectors).

Sure, and you're back to the original statement about needing to copy things to new drives now with more limitations of how it can be done because of RAID10? This never solved any of the original problem, it just extended why you need to constantly migrate to new media over time.