Do high dollar mono blocks truly improve the Sound Quality over the mid tier amps

It's certainly possible, but it will depend on the specific monoblocks.  If the monoblocks are from Convergent Audio, the answer is almost certainly, but everything else also matters.  

The Classe Deltas are not mid-tier.  If anything, they are a bargain compared to

lesser amps that cost more.   B&W frequently pairs their best equipment with the Delta monos — because, according to a Bowers rep Intalked to, they were designed to work together.  I sold more expensive amps to get the Classe because I had Bowers 800D3 with which I was very pleased.  The Deltas were a noticeable upgrade.

The only concern I might have is if the Deltas are a good fit with your Wilsons.  I would suspect so, as they have great ability to push out power, but I don’t know.

I upgraded my PS Audio M700 monos to the M1200s. Wider sound stage with more air. Nice improvement.

@davetheoilguy Thanks for talking about the question I asked and not talking about room acoustics which I did not ask about.  As I said in the OP I love the sound of the Delta amps.  I actually moved from their older model the CT-M600.  When I inserted the Delta's I had an immediate and significant positive improvement in SQ.  That's why I have wondered if there are further improvements to be had. Unfortunately, no one in this thread has responded to my question directly based on direct personal experience with an upgrade.

In a word, no. More expensive amps are often because they use more "interesting" case designs or more colorful shiny bits.