What's the desire of the new generation?
What resolution and refresh rate does the monitor(s) have?
That aside, the RTX 2080 is about the same as a GTX 1080ti (excluding raytracing workloads). Is it sufficient to warrant an upgrade? That will depend on what you want out of it. At the time of release the RTX 2080ti seemed like the one which makes the most sense to upgrade to given the actual increase in performance, as the lower ones in the product stack already have approximately same performance cards in the GTX 10 series.