Ah, my mistake — Bic Camera didn’t acquire Seibu’s site. Seibu Ikebukuro was actually sold to Fortress, and then the property was transferred to Yodobashi Holdings, which is now planning the redevelopment. Bic Camera started in Ikebukuro, so it’s influential locally, but it wasn’t part of the acquisition.

Sources:

Wikipedia – Sogo & Seibu: https://en.wikipedia.org/wiki/Sogo_%26_Seibu SBbit – Seibu Ikebukuro redevelopment: https://www.sbbit.jp/article/cont1/144891