Yes, but WHAT are we “breaking in?”
I own a boars brush (now two!) exactly because it’s stiff and so can generate a GREAT lather from a HARD soap.
If I wanted a “softer” brush, I’d just go straight to a BADGER.
That's the great thing with boar brushes, as the tips split, the brush get softer at the tips and lathers better, but the brush still retains it's backbone. You don't lose the ability to work well with hard soaps.