Most of time, this delay is in peacetime, it makes sense to do a ton of testing, wait until testing results then go to full production. Your primary concern is not spending a ton of money and not getting a bunch of people killed. It's basically waterfall in fighter development.
Wartime is more agile, you quickly close the loop but downside is sometimes does not work and when it does not work, there might be a people cost. US has done it with fighters before, F-4U Corsair was disaster initially in carrier landings and killed some pilots in training. However, this was considered acceptable cost to get what was clearly very capable fighter out there.
Wartime is more agile, you quickly close the loop but downside is sometimes does not work and when it does not work, there might be a people cost. US has done it with fighters before, F-4U Corsair was disaster initially in carrier landings and killed some pilots in training. However, this was considered acceptable cost to get what was clearly very capable fighter out there.