The High Aldwin
I never thought of it this way, but that is very true. From the PHB we have:From day 1 I always thought this was a primary feature of feats.
Many of them in the PHB are features that some classes get but others don't.
Dual Wielder - related to Two-Weapon Fighting Style
Dungeon Delver - related to Thieves' Tools
Great Weapon Master - related to Great Weapon Fighting Style
Healer - related to healing magic by those classes
Magic Initiate - related to Spellcasting
Martial Adept - related to Battle Master
Ritual Caster - related to spellcasting ritual spells
Shield Master - related to Protection Fighting Style
Many of these mimic, complement, or in a fashion replace the features listed. For instance, Barbarians never get Great Weapon Fighting Style, but by taking Great Weapon Master can get a similar "feel" for the concept.
Some of the new UA feats, which more directly mimic class features, are just more obvious about it.