One reason the .45 ACP will be around as long as cartridge firearms are made is that its near perfect as a round for suppressed pistols, suppressed smgs, and even suppressed carbine sized covert weaponry.
The heavy subsonic bullet and low operating pressure seems almost designed for that purpose.
For awhile they manufactured an altered Remington 788 in .45 ACP with integral suppressor as a police counter sniper SWAT weapon.
They used a .44 Magnum receiver rebarreled to .45, and fitted with a bolt from the .308/.243 action. Don't know the details of the magazine.
With the much longer bullet travel some factory loads gave just under 1,000 FPS with 230 gr FMJ.
The Enfield DeLise Carbine in .45 ACP was used to great effect in WW2 and through the brushfire wars of the 1950's.
The US keeps some factory new M3 Greaseguns in the wrap for special operations. The silenced M3 is an extremely effective room clearing device.
The original MAC-10 in .45 is another highly effective suppressed weapon. It was designed from jump to be used with a suppressor. A major role of the MAC-10 was for arming the Sniper's spotter, for taking out any enemy that wandered too close to the hide without alerting the opposition.
I remember one witness to a hit in a car park by a man armed with a suppressed MAC-10 saying it sounded like someone dragging a chain across the hood of a car. The witness did not realise she had just seen a man shot till the victim fell and blood began spreading on the concrete.
The main hurdle in suppressing a 1911 was solved when an expansion chamber was added to the endwipe section. With can attached by a dedicated barrel bushing gas from the fired round drives the muzzle section on the can forwards which acts as a gas assist to drive the otherwise overweight slide/can assembly to the rear. This makes the piece a gas assisted recoil operted action.
Allowing the can to increase in volume also slows down the gas as it expands reducing the sound even more.