The difference between FOSS and proprietary (to me) is the motive. FOSS projects are often created out of a genuine need/want to solve a problem. Proprietary may also be trying to solve a problem (we can't through all of them under the bus because we live in a capitalist system which limits our options, we need to survive before thrive). I still find that proprietary often is just created for profit, and as profit motivated software it has an incompatible goal to actually fixing the problem.
A good (profitable) proprietary app won't fix any problem, but instead exacerbate it to maintain the reason for its continued existence, all while eliminating competition.