I'd say the main thrust of the article is not about cost or complexity, but about the lack of a clear purpose or reason to exist. In the opinion of the article's author, it's not a good educational tool, not a cheap powerful computer and not a real retro platform with a massive game library, so what is it good for?

I tend to understand the X16 as the 8-bit Guy chasing a dream of designing his own computer, which he was successful at - and getting there is impressive. It is not a great product, though, and there are many other hobby computers today available, at lower price points and serving different markets.