Both the requirements and the workload challenges of server-side applications differ greatly from client applications. The JDK has had a pauseless GC (i.e. <1ms pauses) for 18 months now. The need for fast startup and warmup in server-side apps is newer than for client apps, and even with it, optimising for peak performance is still a higher priority than for client apps.
You should expect a runtime that is used more on the server side to be "behind" when it comes to concerns that are more prevalent on the client and vice-versa, and that's exactly what you see.
You should expect a runtime that is used more on the server side to be "behind" when it comes to concerns that are more prevalent on the client and vice-versa, and that's exactly what you see.