I may have it wrong, but in my mind, going from 50 watt amps to 200 watt amps is just a 6db jump in power. Psychoacoustically, its not perceived as twice as loud. And there's really no options out there to go from a 50 watt amp to a 400~500 watt amp to get to that +10db range. Not sustained, but at least just as peak for those transient moments in audio that call for a spike in a range for a brief moment at a higher volume per the recording. There's just nothing economical in that range that I've found. There are 200 watt monoblocks, but that's again not even getting to that +10db coming from a 50 watt amp. And if you were already on a 100 watt, well, it's just a +3db increase, for a lot of cost increase ($400 per amp, or $1200 per three, to get +3db).
So what I am looking at, from this angle, is that say you have a 50 watt amp(s) and you wanted to have a new amplifier with more headroom for transients but you didn't want to have to buy a 500 watt monoblock for over $2k or more just to do that, per speaker, to have +10db headroom basically. Instead, if you had an option to go from 50 watts to 140 watts, you're getting a +3db headroom right away along with maybe 1db more, at $500, for three channels in your L/C/R. While it's also not that +10db headroom, it's +3~4db headroom at $500 with a warranty for 3 years. And that's assuming you were maxing a 50 watt amp. If you were only using 15~30 watts on your 50 watt amp, then something that can get to 140 watts on all those channels is giving you that +10db headroom potentially (14 watts to 140 watts).
Again maybe my thinking is flawed. Then again, if all you needed was 15~30 watts per speaker, then the AVR is already doing that with room to spare, so no amp is needed at all anyways unless you just wanted to expand out and spend money, etc.
I am currently viewing it from the paradigm of something like a X3700H with pre-pro to be able to do 11 channels of processing with supplied amplifiers instead of going all in on a 11 channel native processor that doesn't require an additional amplifier. Being able to put your mains on a fair amplifier and let the AVR do all the surrounds (8 channels 4 surround 4 atmos) for $500 sounds like a nice option, $1500 total for that. Leaves headroom for all.
For context, I use a lot of 50 watt amps. I have several. They do the job. They scream in all my rooms, I've yet to max one in my theater nor on my 2 channel setups. Some of them bridge to 150 watts, and I played with that for a while, but ultimately it wasn't needed. I realize I don't need anything more powerful and an AVR will handle everything, both mathematically speaking from calculating it and from guts-level stuff just experiencing what real 50 watts can do and having lots of room left on the volume to get into the loud listening levels. Needless to say, bridging came with compromise. So I don't do it. The prospect of having 150 watt blocks for $125 each though was too promising not to play with it a bit. But ultimately not something to bother with. But... a 140 watt x 3 channel at 8ohm amp for $500? That's quite literally the same thing as those $125 50 watt amps bridged, but minus all the compromise of a bridged amp seeing a 4ohm load or worse. Sort of fills in where I was looking to be, much better than singles, and there's just nothing else less than $1200 that I can find that will do anything like this no matter the numbers involved.
Personally if I was going to spend $1200 on three channels, right now, I think I would do it with Outlaw 200 watt monoblocks instead of Emotiva. The power difference is ierrelevant, those are just generous numbers from Emotiva, but the Outlaw is being conservative likely, so they're probably equivalent in terms of actual power output. I just like the idea of the blocks because if one were to go bad, the whole thing isn't having to be shipped off or replaced and you can survive. But, I just don't want to spend $1200 on amps that I in reality have absolutely no need for (knowing a 50 watter has plenty of room in my rooms currently). All of this in the context of my current space, I have no need, but my future space in the new house is going to be larger, so I might actually (big might) need a bit more.
Very best,