In other words, is bug just a tag as the other tags are, having no special mod/dev monitoring/lifecycle?
There is no guarantee, but as Ben already mentioned in a comment the developers are monitoring certain tags. This is not only true for Meta.SO, but also for all the child metas.
Still, sometimes bug reports are overlooked. If you notice an old bug report that you think needs some more attention, you can edit it or put a bounty on it if you have meta rep to burn. You could also write the SE team a mail, or ping a moderator you know in chat. We mods can annoy the community team directly, and they can then annoy the devs until they fix some stuff.