They did tell us that we have a grace period after our Switch Online subscription ends. I think it's 6-12 months but someone please correct me if I'm wrong. I don't mind that timeframe and there's no point in having data backed up on their servers if we'll never renew online again.
Anyway, I've seen good and bad comments about the service since Nintendo launched it.
I'm not sure why people complain because they made it clear to everyone before they purchased a Switch.. that our "online experience" was more of a free trial that got delayed (hence why we even had it for so long). With the delay in mind, I didn't mind because more online multiplayer games were available.