I may really be the odd man out, but I'd think absolutely no way two different speakers will ever sound the same even if equalized properly, but for an entirely different reason.
Speakers of the same type sound very different due to design and engineering.
Forgetting types of speakers entirely (box, planar, omni, etc) if you compare two equalized conventional box speakers (eg: twtr, mid, 2 woofs) they'll sound different because of how they work mechanically and move air, even if their respective frequency responses are the same.
Wilsons don't sound like Sonus Faber or Dynaudio or Revel, and keep going. If they did we could all drop $2k on a pair of floorstanders and an equalizer and then make them sound like Rockports. (what a great dream..... :-)