And often not only the price is high but poor reliability.
It is amazing that no one spoke about security in any of the child comments of https://news.ycombinator.com/item?id=49131785
Your definition of fiddling is maybe wrong. Not everyone is Linus S or Jeff geerling to look for that exact DDR stick etc. Get a resonable laptop or mini PC with 2 x drives. Done. Even windows drive share.
A casual user would never buy a NAS at all, since most prefer the ease of something like iCloud or Google. If you buy a NAS you often have a specific reason to (too much data, needing to be able to reach a speed to work off of it, security...) and then the fiddeling becomes an advantage I feel. Yes it's a bit more effort, but you can get something that actually does what you want to instead of what the manufacturer thinks that you want it to do.