Saab (on the Gripen E) are working with what they say is a new philosophy that segregates mission systems from flight-critical functions to a greater degree than in the past. They claim that it will result in faster validation and less expensive upgrades.
Also, consider history. Doing stealth in an air-to-air combat platform is much more difficult than stealth for ISR or fixed targets (moving or relocatable ground targets are in between) because of the need to provide SA and minimize radar emissions. You need sensor fusion and EMCON, the two being related.
In 1985 the only way to do this was with a supercomputer that was so large that it had to be time-shared among all the sensors and the CNI apertures, so the F-22 did this with Ada. The F-35 changes languages but uses the same architecture.
Today, you can put the memory and speed of the central supercomputer behind each of the sensors and feed information, not raw signals, back to the central processor. That option was not around when the F-35 started.