I am awaiting the Konnesseggegegseg... pneumatically actuated valves. Make the valve timing completely independent of crank position and allow for infinitely variable valve timing.

But I tend to agree. Diminishing returns. It used to be "toss some FI on there and it's better", so a few hundred dollar addition created much more power, much more efficiency, and much lower emissions. Now we are tossing a few thousands of dollars at engines and getting a little bit more power, a little bit more efficiency, and a little better emissions.