They already dropped the MGU-H from the 2026 V6 engines in order to convince Audi and GM to enter as engine manufacturers since that component addend extra cost and had no applications in road vehicles so we can assume that they wouldn't have been thrilled to enter if they had to developed V10s now.

Yeah, maybe Ferrari had unlimited moneys for V10 development, but for Mercedes Daimler already is skeptical about the benefits of the F1 program, and Renault's engines just suck this season, and Honda left the F1 program in 2020 then decided to not leave just for Aston Martin but would have probably nto been the case had they needed to switch to V10s.