Sadako of Girth
Extreme Mode
They dont evade combinations of shirt powerful, full bodyweight, high speed punches so easily as there are generally so many of them to fend against and most guard systems fall apart under that pressure.
If those kinds of kicks land flush, then, yeah its often trouble for the Boxer. But the likelihood of the boxer getting to the other guy before that happens is high. And if flashy moves like those fail, they are exposed against the boxer, who wiould be leaping on that countering opportunity like it was the last lifeboat on the Titanic.
A kicker needs to root and would not be at an advantage when it came to facing off against a boxer with good footwork. The lateral movement and hooking of the jab alone would mess up the opponent. Let alone bursting in and out with flurries involving hooks, crosses and uppercuts. And Beddoe and Mickey both have one shot KO power and manuverability..
If anything the Kicker is better off sweeping/attacking the leading leg of the Boxer, who when rooted, will most of the time, have his weight on the leading leg. (Any Boxer worth their salt that has been in situations with a kicker, or who has crosstrained will know to watch for that one)