This is an excellent observation and a corrective to the often-seen and simplistic "x employee is more valuable than y employee." The merits a company places on a project or the valorization of said project is also in play.

What's hard: even when Project A is effectively communicated as the most important thing BigCo does, Project B is still essential to BigCo's functioning and BigCo cannot exist without it, so how to counteract Project B employees feeling either devalued or jealous of Project A?