When I hand the gentile (at the corner heimishe grocery store) my untoiveled keyli & tell him I’m giving it to him on condition he lets me use it forever, and he thinks the whole thing makes no sense, is a kinyan really happening? How different is this from mechiras chometz, where the gentile knows that if he dares approach any of the ba’al habatim in the community for their stash of shnaps he’ll lose job opportunities in the kehila, like helping out at shul on Shabbos, maybe even his full time job at the heimishe corner store? Thank you & be well.
Your point regarding tevilas keilim is a very valid point and discussed by the poskim. In fact the Rema (Y:D 120:16) only allows transferring ownership of a klei to a non-Jew when there is no other option, and the Mishna Berura (323:35) states that one should only rely on transferring ownership of a klei to a non-Jew for a short period of time.
Selling chametz to a non-Jew is entirely different. Over the years, the Rabbonim have perfected and further perfected the Mechiras Chometz Document to ensure that it is legally binding. The chametz really belongs to the non-Jew. In addition, any religious Jew surely does not want to own chametz on Pesach, and therefore wholly agrees to the sale.
All the best