' 'but after all' fits here? If you want to use the conjunction 'but', then don't use the semi-colon. Or, omit the 'but', keep the semi-colon, and thus just leave the two clauses juxtaposed for the reader to contemplate and find the contrast by himself.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.