So what about the hybrid concurrency model--specifically the multithreading, which seems to be enterprise only? Would one expect even higher throughput than what's shown in the charts?

Multithreading is documented as enterprise only. Whether it helps throughput depends on your app's workload. If your app spends a lot of time waiting on IO, such as the database or external HTTP API calls, then yes it will likely improve throughput. Otherwise it won't improve throughput, though it can reduce memory usage.