Actually no, a sensible developer will lock down features at a relatively early to mid-term stage of development because they then need to work on marrying all the elements together and ensuring things run correctly. I highly doubt that an experienced developer will allow Pierre from the AI division pitch a whole new gameplay mechanic in the months or even year leading up to launch because that require a cascade of development work.
This doesn't just apply to game development, and I'm sure the programmers among us on the forum will confirm that locking down features after a certain stage is bog standard practice.
The reason we get frustrated with such Ubisoft statements is because they are clearly talking out their arse. They and other big publishers have a history of doing this because they don't really care about the core issue, just protecting their public facing reputation.
Also, the "don't buy the game before launch and wait for it to get patched and go on special" is really becoming a broken record now.




