IAmSinistar: Odd they didn't mention that in the description of Renaissance
In all likelyhood, the descriptions are written by the publishers. And Nordic doesn't seem to be particularly keen on informing people about the interrelations of these titles, I guess they prefer people to buy all titles instead of just one. ShinyLoot probably doesn't know about such details, for the global market these games are rather obscure products. I have a bit of an advantage there since the series was very popular here in Germany. In any case, even if they know about it, ShinyLoot might not be able to change the product description without the publisher's approval.
Also, I recommend the game. It has bugs which never got fixed, but it provides a fun and rather unique gameplay experience. If "medieval business sim" sounds like your cup of tea, give it a shot.