Ramsey has been heavily linked with a move away from the Emirates next year as his contract expires next summer.
Keown, 52, thinks today showed what Arsenal will be losing if they allow the midfielder to leave.
He said: "I'll be sorry to see him leave - when he comes on he is the icing on the cake.
"I think he's saying in his celebration 'This is what you get if you pay the money.'
"He might be looking at what others are earning. Mesut Ozil wasn't there and he wasn't missed.
"It is out of his hands and he's seeing what is out there."