Although I agree with most of what you are saying.
One i think if you have a one gallon with 65 watts of PC lighting you could keep sps.
The other hand no watts per gallon doesn't mean everything but is a good guide line, kind rule of thumb kind thing.
Most here and on other forums, have the opinion that if you can;t keep it alive then you shouldn't buy it.
This is why so many have posted not to buy without better lighting.
Yes placement will help, but so will better lighting and then you can place everywhere in your tank.
No one wants a tank that the top of it is packed with corals and the bottom has nothing but sand and rock.
There is a difference between can it be done and should it be done.
But yes you can keep LPS under PC as I stated earlier.
And yes the more watts per gallon you have the better the corals survival rate will be.
So you can keep a LPS coral under 3.6 watts per gallon yes. But will it thrive and grow as nice as it might if you had 6.5 watts of PC light per gallon on a 72, no.
The risk is in the buyers hands.
But look at it this way. If people continue to buy corals from the LFS and take them home, and the coral dies what happens? The LFS gets another one in, this is taken from the ocean. If too many corals are taken from the ocean, someday there will be a stop put to it, or the pricing will go way up.
If he buys the coral and it thrive under good lighting and grows to be three times the size frags it and sells to some one where did that frag come from?
Not the ocean.
This is what people are trying to say here.
Nothing more, nothing less.
Do what you want, but everytime a coral dies remember where the next one is coming from.