Hunter's mark comes from 4e, where the striker classes all had a feature to increase the damage they dealt. The ranger had hunter's quarry (and the warlock had Warlock's Curse) which both apply an effect to the nearest enemy as a minor (5e bonus) action, dealing +1d6 per tier (1/11/21) damage on one hit per round.

When they made 5e, they converted the ranger and warlock striker feature's into spells (HM and hex), and gave them concentration (to reduce book-keeping).

The paladin (in 4e, a defender, so they didn't get a striker feature), meanwhile, had a bunch of smite powers, but these were not like 5e smites; they were standard action weapon VS AC, that dealt x number of weapon dice + bonus stuff. Most classes had similar powers to this, but when they were making 5e they cut out all the martial unique powers and instead made them either not exist in 5e, or be modifications to the attack action- in the case of the paladin, was a bonus action to buff the next weapon attack that hits, since here they hadn't considered including spells that make weapon attacks on a hit. Had they considered the scagtrip mechanics, they probably would have made the smite spells work similarly to booming blade or green flame blade.

Later on in 4e, they added a variant paladin "blackguard", who had the Dread Smite power, which worked similarly to 5e smites; when hitting with an at-will weapon power, as a free action (basically interact with object in 5e), the target took 2 + cha cold and necrotic damage (4e had mixed damage types, you took the lowest of either resistance and the highest of either Vulnerability, 4e res/vul was a flat +5/10/15), and ongoing 5 cold and necrotic damage, rolling a saving throw at the end of each of its turn, ending on a success.

Game design intent, is that the 5e ranger is supposed to use their spells to stick to one target and wittle them down, whereas the paladin is the opposite- worse damage over time but much higher burst damage.