More than one thing can be true at same time.
-Frenkie has yet to show he is the long term replacement of Busquets tbh, and yesterday game showed that again.
-Frenkie can still do the job despite some inconvenience, and changes will help to ease things for him.
-Busquets isn't the worst DM in the world, despite all the hate for him. I doubt coaches like Xavi, Lucho etc all playing him based on legacy alone when he is just total crap. Not everyone can replace Busquets and be upgrade.
-Busquets isn't on the required level for Barca anymore, hasn't been for years. At least for a single pivot formation on a consistent basis. He was a slow player and lost even more pace and his quick reactions that helped him tremendously in his illustrious career. Barca need to look for replacement and with limited funds we need to look from inside for current season.
-This is world cup year, Busquets is 43, the man himself will want to be rotated to rest most likely, this alone provides more opportunity for Frenkie, and based on his and team performances we should have a better look on who should have the position for himself based on merits.
-The club should be working on identifying his replacement, while telling the coach that such replacement will need evolve of tactics. No need for Busquets 2 if we can't find him. Busquets wasn't anyway similar to Yaya, Yaya wasn't similar to Edmilson, who wasn't same profile as Edgar Davids who was different profile from Cocu.