hehe right one reason those 40-50 year old amps sound so juicy and forgiving is they have 40-50 year old speakers...
much of the mojo in some of the new 'special' speakers is in cone treatments like 'aging' the cones with fabric softener and setting them out in the sun and various tricks like that ..
the problem with that is that they come new sounding like old speakers, but then they continue to break in and can get sloppy ......
best way is still to do it like jeans ~ you have to earn a good pair of worn ones -- or do it yourself
this is also why I favor separate head and speaker cabs --- once you get a nice speaker broken in you'll want to keep it, tho you may want to swap heads..