Spelunky is a platformer. Isaac, Gungeon, Nuclear Throne are shmups. Citing the
Berlin Interpretation:
"Roguelike" refers to a genre, not merely "like-Rogue". The genre is represented by its canon. The canon for Roguelikes is ADOM, Angband, Crawl, Nethack, and Rogue.
They are a sub-genre of role-playing video games, characterized by level randomization, permanent death, grid and turn-based movement. CRPGs are not such a specific subgenre. You mention RPG is overused but seem to want the term roguelike to be over- and misused in the same way.
On what basis do you think the genre is ''pretty much dead''? Besides it often being the case that these games keep being updated for decades to this day (e.g. ADOM, DCSS) new games and forks of existing ones appear at a slow but steady pace. To name a handful in active development:
Infra Arcana,
Elona+,
Brogue,
ToME,
Caves of Qud,
Tangledeep,
Demon,
UnReal World. If your definition of ''alive'' is being popular; it's a niche genre that has never had many players OR devs, which would make it not more or less ''alive'' than it was to begin with.