You’re right - “middle ground” IS very elusive !
As a young Surveyor I was engaged in checking and agreeing the “Account” of a Groundworker on quite a complex job with multiple variations (Including “moving” 60 houses to a completely different site)
Well The Groundworker’s Surveyor and I went through and agreed what we could, but there were multiple items where he was simply “taking the piss” ! So I paid hiim what I thoght was FAIR ! (which included an element of “middle ground agreement”.
Meanwhile he kept the additional costs (Not accepted by me) within the account and later his boss went to my boss and my boss agreed to pay him half of his extra claim. The Lad however still kept the remaining part (unpaid) within the account and some months later The MD of his Company asked for a “Meeting on site” with My MD to “sort out the underpayment”.
Fortunately my MD rang me to discuss before agreeing and I explained to him that they were “just taking the piss!”
Now my MD and his MD were personal friends and spent a lot of social time together and so I felt strongly that His MD was using that friendship to Bully me and my boss !
A few days later I was copied into a letter from my MD to his MD in which my MD stated that he had Full confidence in “Falstaff’s” ability and any decisions I made on the financial aspects of our contract would be considered by the Board as binding on the firm !
Within a month after that I was promoted and now had autonomy on the whole job ! (Scary stuff )
So the “middle ground” compromise can often be simply a device used by one side to “lock in” a part of their position whilst still arguing to “compromise” on the “other part” !