This is entirely a human construct, we can absolutely make it a level playing field if we collectively choose so.

What a sad comment.

You can make it more level, but in any system constrained by the physical world, you can never make it completely level.

Ever notice that there used to be a lot of businesses with names like "A+ Heating and Cooling" or "AAA Chimney Sweeps"? That was because being at the top of the phone book's alphabetical listing was more likely to get you business since a lot of people would open to a section, start at the top and start calling.

There's only so much shelf space to go around, eventually decisions will be made about who can put their products on a given shelf.

Any large business with the ability to produce multiple different products will inherently have the advantage of getting more shelf space assuming you want to display all products.

But even assuming you just wanted your shelf space to be a bunch of "per company" catalogs, businesses with more money to spend on glossier catalogs, or brighter inks, or more variations so thicker catalogs will have an advantage.

Then there's names and numbers. Hooked on Phonics gets a leg up on every other competing reading program because they got the phone number that is 1-800-ABC-DEFG, no one else can have that number. The lawyer who gets 1-800-555-5555 (or other similarly easy to remember number) has a leg up on anyone with a random number out of the phone company's inventory.

But I'm curious, what would this perfectly level field you envision look like? How would these sorts of problems be solved?

Until you try to grapple with real world problems like limited shelf space, limited directory space, how the ads (ahem sorry, directory entries) should be sorted, how to deal with setting boundaries around local directories, etc.