Those groups are not the ones whose advertising includes making posters. That's not where they sit in the industry.

Advertising posters, such as found in game stores, are marketing material that is often licensed by the company distributing the game. There are various reasons why the contracts require the items to be returned or potentially destroyed. This has been the case since the dawn of film advertising in the early 1900s. Over the years a few of the reasons for the requirement have changed; the costs have dropped and the materials are less-often reused, but others of the business reasons remain. They are meant as advertising material, not as consumer goods.

Those groups are not the ones whose advertising includes making posters. That's not where they sit in the industry.

Does one simply have to buy posters on Amazon to resolve this?

Those groups are not the ones whose advertising includes making posters. That's not where they sit in the industry.

You mean the software companies?

Does one simply have to buy posters on Amazon to resolve this?

Unity and YoYo Games market to developers and businesses. They do not typically advertise with posters for Unity or for GameMaker:Studio.

Retail games get posters and ads made up for retail stores, such as GameStop or ToysRUs. They are part of the advertising campaign for finished games.

Publishers and distributors are the companies that work with marketers and retail outlets. They make deals with retail outlets about promoting games. Normally those contracts require the return and/or destruction of marketing material.

Many companies also produce commercial posters for their games which are for sale. Sometimes you can ask the game companies for a bundle of promotional materials, and if you talk nicely to the right people they might send you some. That will be for retail products that already have posters. So you might figure out who the producers or social community managers are for your favorite games and contact those individuals directly.

Alternatively, call up your favorite game stores and ask if they have posters for sale. Many have a bin full of them. Again these are posters for the retail products, not posters for game engines, because game engine companies don't typically market to game consumers.

Also you can try on eBay as well to resolve this.

Also you can try on eBay as well to resolve this.

Same as Amazon, right?

Also you can try on eBay as well to resolve this.

Same as Amazon, right?

Yeah. Carry on!