I’ve been a member of different public sector unions for the past twelve years, both as rank-and-file, volunteer, paid staff, elected official, dissident, and now back to rank-and-file. So yeah, I’m a fan.
Back during the Wisconsin/Ohio fights, I wrote about why I think they’re vital institutions here, here, and here.
As to why they’ve endured, that’s partly because private sector unions were heavily concentrated in manufacturing and other industrial sectors in the midwest and northeast and thus took an outsized whammy when deindustrialization hit those regions in the 70s-90s whereas public sector employment has held up, and partly because public sector unions have an easier time defending themselves politically (they can work through state and local government rather than just federal government, their opposite numbers at the bargaining table are local/state electeds not multinational corporations, etc.).