sorry son your bias is blinding you. The couple dozen yes but the latter batches until the current one can be refit with updates and upgrades. The US model is to buy then upgrade as it progresses.With the F-35 we talk about the first few hundred units, as useless for even training.
They will do good service as static display , I'm sure
Russian air forces are far more limited in buys. Every aircraft they buy at max a just over a hundred then move to export. As such each production SU57 counts far more to the program than batches. It is a requirement of the service based on needs including not exempting budget. If you believe that you can build as many as you like without considering budget you are delusional.