I wouldnt call Mario or Ratchet ambitious games.
Well if you think Rare is more ambitious than Insomniac and Nintendo I guess we don't have much to discuss.
Thats the problem with your debate. You assume not being ambitious makes the games bad.
Rare are not known for releasing sequels after sequels. Even under Nintendo, they move on to new IPs and game designs. Thats why they have one of the most colourful collections of IPs in the industry. Weather they come out good is debatable however thats their buisness structure.
Rare simply dont make those type of platformers anymore.