Today’s RPGaDay 2021 prompt is “Substitute”. What a tricky prompt! I’ll do my best regardless.
I think there’s no real substitution for the kind of experience that a tabletop RPG offers, which puts it in a category of itself. For me, movies and series are somewhat interchangeable nowadays, given how much the production quality of series has improved over the years. I love books, and I would gladly read either a traditional novel or a graphic novel, as both would cater to the same desire I have. I don’t know of anything that would exactly substitute the experience I get out of a tabletop RPG, however.
Computer RPGs offer something vastly different to what tabletop RPGs can offer. Firstly, a lot of computer games are termed “RPG” because they have a point-buy system in their leveling-up mechanics, while the rest of their gameplay can be quite traditional computer game stuff. Secondly, the RPGs that do have to deal with role-playing, and are modeled after tabletop RPGs, are often focused on tactical combat simulation. There are scant few that actuall model the narrative and character0based roleplaying that tabletop RPGs can offer. And then still, due to the nature of computers, the games are quite limiting in their possibilities.
Nothing comes quite close to playing an RPG around a table (though playing RPGs online has gotten pretty convenient too, lately). It’s a wonderfully unique experience for which there is no substitute.