Some of you are also mixing concepts.
Quantity VS Quality.
Sailing sold lots more than Shangri-la because STP had a Dire Straits single like What it is. But in terms of solo artist, Shangri-la or Get Lucky, both show a more nature artists, with more complexity and really far from the Straits style.
That's my opinion, and I know it's shared with many other people, with many others fans. I even know fans that didn't buy any MK record after Sailing, because "that was a different Knopfler"
I'm sorry but I can't consider than STP, the second solo record, in a long career of many records, where he evolved a lot, is his best. No. It's his more commercial one, hence the sales.
You are entitled to have another opinion, of course, but you are wrong