The decision process does not start on the date that the SDSR report is made public, enough time has already been lost.
A point well made; a point lost on many, including the hapless authors.
To be specific...
The last operational MPA we flew was the Nimrod MR2 (retired 2010)
The requirement to replace that aircraft (ASR 420) was issued in 1993.
That was 22 years ago.
We're still waiting.