http://grandcypher.com/2021/05/11/year-7-in-review-granblue_en-interview-with-tetsuya-fukuhara-5-11-2021/
This guy doesn't even know what he is talking about. Implementing rollback is easy af and game developing today is much easier. Even skullgirls, a 2013, game has rollback. What a hack.;)