Absolutely not, and there are plenty of easy counterexamples.
If you've ever raced track, team pursuits start from a dead standstill. You have to expend a ton of force to turn a huge gear, and the contribution of the lifting leg is crucial to getting up to speed. Of course it's not going to contribute as much as your lead leg, but all four of your limbs are at maximum exertion getting the bike up to speed. Even not racing at a track, you can test this on any road bike. Shift into high gear, come to a standstill, and time yourself getting up to speed.
Another trivial counterexample that anyone (with clipless pedals) can test is a hill climb. Being able to lift on the upstroke is an enormous additional benefit and the difference can be easily measured and proven. Perform a lengthy climb with and without involving your trailing leg, at a given level of intensity. Repeat this multiple times, and it will be patently obvious that your trailing leg is performing significant useful work. The steeper the climb, the more important this is.
Sprint finishes are another place where this is critically important, but it's harder to set up a simple test.
What all of these have in common are situations where outputting a higher force is more important than long-term endurance. Lifting on the upstroke is difficult to do at high pedal speeds, but at medium or low pedal speeds, it's a clear differentiator.