The new graphics cards from Nvidia didn't actually improve the performance you get at a given price level by much. The RTX cards do include special hardware to accelerate new raytraced lighting effects, but those effects cause a big hit to performance, only 3 games support them so far, and the visual improvements tend to be relatively minor considering the large performance hit. So, many would argue that those effects are not worth enabling even on the newer RTX cards.
As a result, the 1080 is still quite relevant. A GTX 1080 generally performs a little behind an RTX 2070, so I would say it's worth a bit less than what those are currently selling for. Since those launched for a higher price than what 1080s were typically selling for at the time they came out, you likely didn't waste your money.