Is there any truth to this question?

You can also over-power your speakers too. I wouldn't exceed the power ratings for your speakers however it is also true if they are under-powered you can easily drive the amp into clipping especially at higher volumes and this will in turn destroy your speakers. Many people that own Vandersteen speakers like the way the McCormack amps sound with them.

FWIW, there is an old audiophile axiom: that one should start with at least 2 X the minimum power recommendation of the speaker manufacturer. Though a more accurate deduction can be made with more tangible information such as room size, etc.. Surprisingly enough, I've found this seemingly crude rule of thumb to be consistently useful.

Sounds like a reasonable start!

Last time I visited with Roger he was using the RM-10 to power his 74 dB ESL loudspeakers. We were listening at a very moderate level in his room and there were no hiccups coming from that amp that I could hear. Sometimes you can be surprised by amp/speaker combinations. I myself would think 100 watts minimum in this case, but the RM-10 easily had enough power, perhaps not to rattle the walls, but definitely comfortable listening.

Regardless of the speaker's sensitivity I have found not driving your amp too hard and having more power and headroom available is a very good thing. In my current rig a highly touted 70 watt tube amp was displaced by a Hybrid amp with 4 times the power. The more powerful amp was not taxed as much, and I think since it was not pushed, just sang with more ease and pleasure.

Extra watts and headroom can be a very good thing especially with large orchestral music and the like. Same is true for solo piano turned up to louder volumes.