Any sort of worthwhile plan is dynamic if it is meant to cover a decade or more. Usually, when it is drafted, it should show the intent without the detail for what should exist in 10 years' time.
Sometimes other factors intervene to prevent full implementation of the plan; lack of anticipated funding, a natural disaster, change of ownership, political pressures or changes in the political landscape after elections.
That's when changes to plans occur, and reviews are a required to (a) judge progress, (b) value for money (c) what has worked and what hasn't and what can be learned so implementation of the latter stages is more efficient and (d) assessment of feedback from users either through survey or observation.
I am afraid a lot of cycling infrastructure is developed for opportunistic political gain, especially on the left side of politics, and it's then when the approach can be haphazard and in some cases lethal. I can draw parallels between this and an Australian program to install home insulation under the previous left-wing government that killed some people (yes, killed them), and left many financially ruined because there weren't adequate planning and checks and balances in the process.
I am a firm believer in incremental changes to road landscapes, but with a long-term plan that helps govern that implementation. It may look at road renewal programs that are already in place and integrating cycling facilities into those. It may look at planning schedules for real estate development, and integrate facilities into those. It may mean persuading government to change planning regulations to include cycling facilities as a matter of course.
However, the greatest barrier to all this is the disintegrated approach taken by the cycling communities (plural) who all have their own self-interests and cannot see the big picture.
All this based on my personal experience.