At a well-run club, there would be no false dichotomy between keeping Ozil+Sanchez for $0 v selling w/o replacement last summer for $150m. Obviously, there is such a thing as selling and replacing (what big clubs do all the time). It's the corporate equivalent of recycling possession. Players come and go, the important thing is to preserve transfer value in the form of new players of similar or better quality. I suppose that sounds like a Ponzi scheme, too, but there you go.
The fear of selling that seems to plague many of us evinces a small-club mentality, a fear that we won't/can't attract great players. It becomes self-fulfilling if we destroy $150m in transfer value like we just did, and then can't afford superstars in future. We did well to bring in Lacazette, and we could've gone for any number of attacking players in addition.
I can hardly believe the stupidity required to leave us in a situation where we lose not one, but two world-class players in their prime in the same summer for nothing. Not sure that's ever happened in the history of football. And for what, to ensure Europa Lge qualification next season?