All epidemics follow a natural curve where the pathogen initially spreads exponentially, but slows down over time as R(t) decreases due to the increased presence of population immunity. That creates a natural drop-off, and given that mandates and other "public health" responses tend to occur late in the cycle, it gives the impression that the natural drop-off is attributable to the intervention. It's rarely the case that it truly is. (By the way, if you look when they reverted to orange and then yellow the spread did not pick back up, which supports what I'm saying about this just being the natural epidemic curve)
If we want to talk masks specifically, the evidence that outdoors transmission of COVID-19 is rare anyway, and furthermore the purported mechanism of action of masks only works if (a) large respiratory droplets are the primary transmission mechanism as supposed to aerosol spread, and (b) people follow rigorous protocols to avoid contamination of the mask or from the mask. (b) is certainly not true, and (a) is likely not true when you look at the overall evidence of how viral spread (and specifically SARS-CoV-2) spread occurs.
Indeed, if the primary transmission mechanism is aerosol, masking could and likely would worsen transmission. The logic is pretty simple: masked individuals breathe more deeply to get the same amount of oxygen as an unmasked individual (this has been shown in numerous studies due to the local co2 buildup), meaning masked individuals move a greater net volume of air. Given masks cannot filter out aerosols, that greater volume of air will translate to worsened spread. This is made worse by the fact that when speaking to another individual, you have to speak louder for them to hear you through the mask.
(Sticking with the aerosol reasoning, there is one possible tiny benefit which is the masks still do alter the path of the aerosol; it smokes out and around the mask wearer rather than it being as directed as unmasked aerosol. But it's a very minor effect at best. You can look at any of the many videos of someone hitting a vape and then exhaling out of their cloth mask/surgical mask/bandana and you'll see what I mean)
So, in conclusion, no it's really not as simple as you're alleging, and this type of tenuous speculative post hoc ergo propter hoc reasoning is all too common these days unfortunately.