There are plenty of fires east of the Rockies, you just have to look at the correct resource to see whats happening. However, because of the dryness and terrain, western fires tend to get larger, faster and are much harder to put out. Western fires can burn for weeks or months. Typical eastern fires are noticed, contained and extinguished before the grow to significant size. It also doesn't hurt that the vegetation is not as dried out and tinder ready as the west, but there have been numerous large fires in eastern mountain areas. Gatlinburg TN is one I recall simply because Dolly Parton dumped buckets of her own money in to recovery efforts for the region.
Check the US Forest Service map of fires and incidents for info.
https://www.fs.fed.us/science-techno...re/information