[dingaling]

The F-111 was a capable strike aircraft once they worked out the intake issues, but failed as a Navy interceptor and was inadequate as a strategic bomber

The C-5 suffered expensive wing cracking issues early in its life and even after that was fixed it had the lowest reliability of any Air Mobility asset

The F-18 was short on range and bring-back payload compared to its predecessors and had to be redesigned mid-life into a basically new aircraft

The B-1 was cancelled once and brought back as a less capable but horrifically expensive-to-maintain aircraft that failed to replace its predecessor

The F-14 was cursed with inadequate engines that hampered its flexibility and it had crippling maintenance requirements

The C-17 is one of the most expensive methods of moving payloads ever invented, since it is compromised by tactical requirements that aren't relevant to its actual role

And those are just off the top of my head.

So much in invested into so few platforms these days that they simply have to be made to work to a tolerable level. The fact that they remain in service is more a reflection on need rather than merit.

[p_l]

And in case of F-14, it was politically motivated penny pinching that led to TF30 engines being used - when they were supposed to only be temporary option to make testing quicker and cheaper.