This isn't surprising. Raja just didn't have a good reputation after the Vega launch. Sure, it's great for compute, but it undelivered due to HBM2 underperforming, which bottlenecks the enitre chip. I get almost 20% gains just from overclocking the memory.
AMD needed a change, Raja may have not have delivered but then again AMD didn't fund RTG worth a damn. Now that they have some much needed cash maybe they can stop outsourcing to save costs in the RTG group so darn much and get the best people for the job.