Avatar is an "affordable but good" approach. Not "boutique" and never claimed to be.
Their 112 & 210 are the same box, different baffle cutout. Their 410, 212, & 115, same thing. All are "close enough" to produce satisfactory results with their drivers, while none being "ideally optimized" for any of them, which would drive the price up at least 2 times, probably more.
This way of doing it is not out of the ordinary at all, in fact it's very ordinary. Just look at offerings from other companies. GK, Ampeg, Carvin, Ashdown, ... hell even Mesa and Aguilar.
If people want to complain about "cookie cutter boxes", they might should direct their righteous indignation towards companies following this practice while claiming "boutique" or "superior" status...or at least charging for it, rather than downtalking lower tier companies just making bass gear that gets booties shaking at the local pub that common people can actually afford.
The vast majority of design in most any decent sized company comes in the design of the driver itself, rather than just "WinISD and a box".