system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] I have a lot of questions about the EXO-7 Falcon program.

Why did the Army shelve the EXO-7 Falcon program? If it was dangerous, why didn't they destroy it instead of putting it in a vault? Why haven't they restarted the program now that it is obvious how awesome it is?
gpt
The original system was probably greatly limited in terms of range/flight time and payload, which made it of considerably less use for many military purposes.  Assuming the system was as expensive and difficult to use as it looks, they could have figured that it just didn't offer enough value over mature helicopter platforms *as yet*.  What's more, the appearance of weaponized consumer drones and other small+quick airborne threats has lead to an opposing proliferation of light point-defense systems for hitting small targets at close range.  A lightly armored human with no countermeasures who is several times the size might not fare so well against such systems.

Sam's wingman got taken out by some insurgents dumbfiring into the air, likely confirming assumptions that using the Falcon suit would be suicide in too many circumstances, unlike something more heavily armored and lower profile like Iron Man armor (which there almost certainly is/was an ongoing program to replicate). Sam seemed to prove that wrong by somehow evading the CIWS of the HYDRA helicarriers, but he is an exceptionally gifted pilot.

Tl;Dr: The system was very promising but seemingly ahead of it's time (and perhaps competing with a sexier program to replicate Iron Man-esque power armor) so after a performance that confirmed the concerns of the USAF brass they shelved it for a later date.  They didn't destroy it because it had some promise and there was no reason to do so, the military saves all sorts of abandoned tech just in case an application appears.