Actually it is not. As our CEO has stated in another thread here, the whole concept of the Sitefinity 4.0 pricing was to settle it from the beginning and not change it afterwards, even though we will continually add more and more features.
We are definitely aiming to enrich Sitefinity 4.0 with everything that Sitefinity 3.7 currently has, but we are far from the thought of stopping there. More to be announced in that roadmap that Georgi mentioned. As for the marketplace - third party modules and new value-adding features will be made available there. However the core functionalities a CMS should have will be added directly in the product (once again - without affecting the price at all).
Grisha 'Greg' Karanikolov
Sitefinity Solutions Consultant