One of my favourite examples of this is still Rust. Sure, it’s not a perfect game, I don’t always like the updates, but do I feel like I got my money’s worth, from a purely online game I bought in 2013 and can still hop on with thousands of other people? I do.
Since nobody else has said it, Titanfall2. Not a long story, but it’s an absolutely fantastic 6 or 7 hours. Usually it’s like 5 bucks during a sale.