That makes a lot of sense in theory, but Pentium 4 HT was a real evidence disagreeing with it. Netburst have had horrible IPC, so in theory HT should've brough

That makes a lot of sense in theory, but Pentium 4 HT was a real evidence disagreeing with it. Netburst have had horrible IPC, so in theory HT should've brought big improvements, yet in practice it didn't bring significantly more relative performance improvement than HT implementations of later Intel cores with much better IPC. Adding to that SMT in Zen cores have brings slightly better relative performance compared to Intel cores (and Zen doesn't have as terrible IPC as Netburst), I think SMT implementation is not as trivial as we thought and before and its implementation indeed matters.