A few reasons why pump action rifles were never very popular:
Awkward in many natural rifle shooting positions (prone, seated, kneeling) where the shooter tries to take all movement out of rifle with the support hand serving as a rest. Not an issue with close in shotgun work and shots being taken standing and firing at moving targets.
No mechanical leverage to chamber or extract cartridges - unlike lever actions and bolt actions
Complexity - if you are manufacturing a pump, you might as well make it a semi auto instead. Much more appealing.
A few reasons why pump action rifles were never very popular:
Awkward in many natural rifle shooting positions (prone, seated, kneeling) where the shooter tries to take all movement out of rifle with the support hand serving as a rest. Not an issue with close in shotgun work and shots being taken standing and firing at moving targets.
No mechanical leverage to chamber or extract cartridges - unlike lever actions and bolt actions
Complexity - if you are manufacturing a pump, you might as well make it a semi auto instead. Much more appealing.
The biggest advantage of a pump over a lever is that neither hand leaves the weapon, which gives consistency to grip shot-to-shot.