If I had the choice, I will go for the "suffering" route...
Designing complex equipment is not building road, you can't halve the time by throwing men and money at it.
It works if you have under-capacity, that is project undermanned underfunded equipment outdated etc:
However, if not:
1) There may simply not be enough trained and capable people to do the job. China currently has WS-9, WS-10 (and variants), WS-13, WS-15, and half a dozen smaller projects.
2) Project management framework may not exist (i.e. can run 100-designer project well, but cannot scale).
3) Related to above, after a point adding MORE designers just produces paralysis. Imagine 4 teams of engineers working on same fan blades... exactly.
4) After a point you may simply have to opt for parellel projects - that was often done historically, Soviet Union had for example in 1949 two teams working in parallel on rockets, one of Germans one of Russians (Russian team made better design by the way). This is good insurance, but fantastically expensive.
5) Drastically increasing funding may be counterproductiv. If for example buy in bulk much state-of-art equipment instead of buying bit by bit incrementally, produces paralysis because now need to trained new people to operate equipment, relearn usage and integrate equipment within existing system. Bugs may take months if not years.
6) Funds may be mis-spent. Few project managers ever refuse extra funding. Then becomes exercise in self-justification of funding - buying marginally useful equipment, giving selves raises, new offices etc.
These and many other reasons are why one cannot simply plough money into projects and expect proportionate returns.
Likely analysis was something like this:
1) PLAAF looks at threat, give report of what is probably needed
2) They check how much funds are available, remember if you axe 1.5 billion engine deal is no assurance all money goes into R&D. May go to bombers, may go to Rocket Forces, may go to Chengdu hiring assassins to kill you for delaying and probably killing J-10 project for years.
3) Decide what to do with this money - buy all Russian aerialengines? Can Russia even deliver so many within timeframe you worked out? Go to all domestic? Can the design bureaus absorb so much cash? There will be NO engines.
4) Because design bureau is of such size, to fully fund it and give reasonable incremental upgrades would cost so much, Russians can build so many engines, Chengdu can build so many airframes, how many regiments in PLAAF needs replacements, how urgent it is to develop doctrine... you come up with balance.
I hope that helps explain my comment.
