Core technology is usually built on older technology (C, C++) to avoid platform risk. The flashy product stuff is built on the latest bits for execution speed.

Core technology is usually built on older technology (C, C++) to avoid platform risk. The flashy product stuff is built on the latest bits for execution speed. The best C++ architects/leads are in their 60s and the best React Native architects/leads are in their 20s or 30s.