I've pondered this a bit. That doesn't mean that I'm correct here ..but these are my musings on the topic. In olden days, when our carbs had external vents, a clogged air filter meant sucking fuel excessively. When they went to internal vents(at the same atmospheric pressure - inside the filtered air zone) ..the rhetoric (mostly) evaporated from the media arm of the aftermarket as, I suspect, the major impact of the effect.
Now, I imagine, a restrictive air filter adds to throttling losses ..and alters MAP readings. Maybe only in terms of inches of water column at first ..but I'm sure that it's a progressive condition. Once you exceed the parameters of the mapped fuel curve ..a speed density system will just go to the max settings in corrective action. Something we would term in my former instrumentation calibrations as "OUT OF RANGE". I don't necessarily understand the dynamics of it in a racing situation ..but one should reason that you want fractional inches of negative water column across your air filter. Assuming that your OEM designed your plumbing appropriately, that's probably (my speculation, I've never researched it, nor tested it) all you'll see.
In a street piece, I'd say you're looking at some added effort in just getting the air to the engine on top of any alterations to the MAP readings. You're simulating a higher altitude for the engine ..or so I reason
Again, this is just my backburner pondering on the topic. It's not any enlightenment. That, I'd surely welcome from someone who truly knows. I'd also love to have the refined instrumentation to explore this at the end user level ..but that's beyond my means.
Edit: In the terms of a diesel, there is no inherent throttling loss due to no throttle. You are introducing one with a clogged or restrictive filter. Keep in mind when a diesel owner says that they have no "compression braking" ..they really mean vacuum braking. They have all the air and compression that they need 24/7 whenever the engine is turning rpms ..gobs more than any gasser..what they don't have is a butterfly to produce vacuum braking.