While it's interesting that the term RMS power is a misnomer, it is at least consistent. We are still at least comparing apples to apples. I suspect that's all most consumers care about. As long as I know everyone is using the wrong term in the same way, knowing that one amp is rated at 25 wpc rms and another is rated at 80 wpc rms, that is providing me, the consumer, useful information.
RMS Power?
I often see power specifications like "100W RMS". There is no such thing as RMS power. Of course, you can calculate RMS value from any curve, including power curve, but it won't represent anything. "Real" power representing heat dissipated in resistive load is "Average Power" Pavg=Vrms*Irms. In case of sinewaves Pavg=0.707Vpeak * 0.707Ipeak = 0.5Ppeak, or Ppeak = 2Pavg.
Term "RMS Power" or "watts RMS" is a mistake, very common in audio.
Term "RMS Power" or "watts RMS" is a mistake, very common in audio.