In a lot of places in Germany public transport was only restricted to using N95 masks. This summer in Berlin all the stores required N95 masks, as did universities. They have relaxed the rules since then and you can see in the recent infection statistics how that worked out for them.

In the US, you can hardly get them. Amazon was restricting them to medical professionals until recently, and all the local stores have been out of stock since spring 2020. Now, if you currently look at Amazon for 3M N95, you'll see that a lot of the purchasers are doubtful that the products offered are genuine.

We've had two years to increase the output of N95s and expand the hospital facilities to handle severe COVID. Almost nothing has been accomplished.

Right now FP2/N95 are the only masks allowed for adults in public transport/supermarkets in Bavaria Germany. Cloth or surgical mask are treated like wearing no mask at all, unless it's a child up to a certain age.

Compliance in public transport and supermarkets is extremely high, pretty much never see any adult with just a mask, everybody wearing actual respirators.