Apparently in your imagination.
Making blanket statements is just foolish. Will you taste them at 5% in a complex or full flavored recipe? Unlikely. Will you taste them in a simple or nuanced recipe? Most will.
You should also note, it took 3% more carared, 3% more melanoidin and 0.5% more carafa sp to make the pilsner base beer taste like a Munich base beer. If Pilsner and Munich tasted the same, then the beer with the extra specialty malts should have stood out. Unless you are suggesting those three malts don't affect flavor either...
Have someone who brews good beer do a smash lager series for you. 100% Pilsner, 100% Vienna, 100% L. Munich and 100% D. Munich. They all taste different and have their place in brewing for a reason.