Question about wpc on tube amps

I have been kind of looking at tube amps based on what people seem to think about them.

Here is my question- whenever I look at the wpc, they are remarkably low vs. a solid state amp for the money. 

It leaves me scratching my head. Then, somewhere I read that you can't compare a tube amp with a solid state amp . Something along the lines of "10 watts of tube power equals 100 watts in a SS amp". 

What? Is this real?  Seems unlikely to me. 

Are the wildly low power ratings on the tube amps I am looking at simply due to the fact I am looking at $1,000 amps vs the bajillion dollar amps you guys buy?

Would I be better off spending the money on a tube preamp for the "tube" sound I always hear about. 

I am running Magnepan . 7's  with a Bryston amp. Since the . 7's are power hogs are tubes even a realistic thing for me in my lowish budget? 

Thanks!