It's only arbitrary when using it against non-comparable stats. For example, comparing shot percentage to goal save percentage is pointless, because they measure completely different stats.
A quick search shows that an NHL team will generally get around 30 shots per game. If your goal save percentage is about 45%, then you're not going to have a career much longer when the rest of the league hovers around 94%.
A quick search shows that an NHL team will generally get around 30 shots per game. If your goal save percentage is about 45%, then you're not going to have a career much longer when the rest of the league hovers around 94%.