It’s surely ego, but I don’t get it. MLB closers can be more celebrated than starters in some cases. Mariano Rivera is more remembered than most of the guys who started on his Yankees teams.
Eric Gagne is the only dodger pitcher I remember from the early 00’s besides the Japanese guy who came over that had press for weeks when I was a kid in the late 90’s.
Even recently, Felix Bautista is the most popular oriole.
Being a closer is arguably preferable imo. You get the most high leverage situations, the most praise (only if you are successful, much like being a QB.), and the longevity you have compared to starters is nothing to scoff at either.