Varies enormously by location and time - it's not that supply is infinitely lacking in certain areas (or you'd see shortages so total that crimewaves would've resulted by now), it's that the supply is starting to limit itself and starting to collapse therefore you're seeing less of certain items in a given area, less of a certain type of item in a given area, so on and so forth - personally for me, I'm noticing some stores are completely and utterly empty very often while other stores maintain (most) stock and this is due to whoever they receive supply from - you've got major suppliers on the EC like McClane that are enormously struggling to find drivers right now for anything at all (and they're also struggling to find new trucks, apparently.) so any market or retail establishment that receives supply from them is starting to look barebones on the EC.
All of this is something in still very early stages of occurrence so, yes, the areas in which one feels the impact will vary and limit themselves by local supply, chosen out-of-state suppliers, etc. but rest assured, if it hasn't reached you yet, it most certainly will at the rate we're going and for someone to point out that the shelves are empty in the area isn't doomerism, it's fucking observation, my guy - it's walking into the nearest supermarket, seeing that the shelves are empty and noticing that shelves are also turning up empty in various other parts of the country with various other parts of the media constantly talking about a collapsing supply chain, it isn't fucking doomerism to walk outside, see storm clouds, and say "oh boy it looks like storms are coming"; where I am, empty shelves didn't actually start appearing up until just a week ago but empty shelves started being an issue for major metropolitan areas on the EC much earlier than us or really anyone else in this country - in the case of the establishments I referenced above that do maintain stock? They're slowly running out of a given item while other stock is thus far fine or unimpacted but also often receive warnings directly from their own upper-management that supply chain issues are causing more and more pressure and woe on their own personal supply chain.
We've got nearly 100 cargo ships completely jammed and congested at Californian ports, with no relief on the way - the supply that's here right now is capable of keeping quite a few areas of the country logistically supplied but we don't have enough coming in to actually replenish these lost supplies; I don't understand how someone can take a fucking country as large and complex as the United States, state 'haha this isn't happening in my immediate area, thus there is no problem, despite it happening in 10 given other areas, and will assuredly never impact me haha' without being literally fucking lobotomized of intelligence and observational ability.