I disagree with this. I have managed to get by quite well with my 4-bay Synology for over five years. They still even provide updates for it. That said, most of the "work" is done on a server of its own accord, and not on the NAS. More than anything, this server will be getting an upgrade later this year with a newer workhorse from either Dell or Supermicro to better suit the needs of virtualization and LXC, and on-hardware AI with whatever consumer PCI cards I can get my hands on.
I don't foresee a need to upgrade outside of disk replacements for storage for another few years, by that time it may be time for 10GigE at home and then, we can talk upgrade.