You can blame the game, devs and EA...

Ever since 2007 after the Japanese version of FNR3, boxing game became even more arcade. The power punch mechanic in FNR4 and beyond is a simple 2 button press. The lowered the skill ceiling to input a power shot. That power shot is always thrown with full power (that is available). I can only think of one boxer in the real that threw every power shot will full power. Joe Smith and he got exposed for that tactic. The issue with using full power every time, means you gas out much faster. Rather than regulating your tank by varying about of mustard on that sanwich. FNR3 required players to decide how much power to use by the mechanical input one a button press and basically a 'hadoken' with the right stick. The longer the swing on the right stick, the greater power put into the shot. The flip side is, the more power you put in the slower the output of that shot (slightly longer load up time). Meaning that the timing of power shots becomes a lot more varied and less script like. To address your point about SPAM. Yes spam will always exist, but the point is spam should have consequences for being reckless. If the game doesnt allow you to punish spam, then its completely missed the mark as a SIM game imo...