I’d wager that a rigorous statistical analysis would prove that the concept of “ending a losing streak” has no great impact on the overall number of wins. A win is a win is a win, just like a hit is a hit is a hit. The concepts of “clutchness” and “pitching stoppers” just don’t bear out. If makes for compelling TV, but over 162 games all those anolomies balance out.
I think earlier statistical analysis has disproven the notion of the “hot hand” (in the NBA, anyway), so that wouldn’t surprise me.