Klaus Schmidt, who began the excavations, noted similarities in stone tools at Gobeckli Tepe and other sites which was one of his methods for dating. (see: https://www.smithsonianmag.com/history/gobekli-tepe-the-worlds-first-temple-83613665/). Some of the male figures bear similarities to those found elsewhere as well. So clearly, Gobeckli Tepe was not isolated. From the Gobeckli website, the archaeologists date the most recent phase to be 9,600-8,000 BC (see" https://tepetelegrams.wordpress.com/the-research-project/ which also notes the comparison of carved figures). Dating these sites is imprecise but that could indicate only a 500 year gap which may actually be much less if estimates at Gobeckli Tepe and Çatalhöyük are off-- which is a distinct possibility.
Further, much of Gobeckli Tepe is unexcavated so it is risky to draw too many conclusions. It may have been abandoned in 9,000 or even 8,000 BC. There also may be other as yet undiscovered sites that will establish a clear line of development. Jericho and Çatalhöyük suffered devastating destruction in ancient times, there may have been much more sophisticated artistic endeavors that were destroyed, taken away or have yet to be found. Gobeckli Tepe was intentionally buried which likely means more is preserved.
I agree with everyone here that Gobeckli Tepe is fascinating, leaves us with many more questions than answers and may imply a different societal evolution than previously supposed.