If the answer is "very few" then that might be an early warning sign you're working for a product or org that is headed for serious problems. As a technical IC who can't hope to solve those large scale management problems, this can be useful a red flag. Don't wait for shit to hit the fan to leave.
I have seen a large scale failure of this kind and the items listed here line up very well with some of the root causes I observed.
- Is the roadmap flexible or iterative? The roadmap was hard, aggressive business targets.
- Are the roadmap initiatives scoped and prioritized based on evidence? The roadmap initiatives were derived by working backwards from business targets and then evidence was found after the fact.
- Does the roadmap identify major dependencies or risks? Many risks were identified much later because techincal teams were not part of input to initial planning.
- Does the roadmap feel aggressive but achievable? Aggressive but not physically possible.
- Does the roadmap take on appropriate risk? No, there was multiple possible independent points of failure.
Anyways, if you ever see this kind of product culture I suggest running for the hills unless you like having your time wasted. And if you are a technical manager I hope you push back like hell when presented with this situation.