system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does A4 paper manufactures compete with each other?

From my understanding all brands are indistinguishable from each other in terms of the "product" (its just a piece of paper), and I assume that users just buy the one that's the cheapest. So how do industries compete? Is it solely about price controlling?
gpt
That's a big part of it, yeah. If they can find a way to keep costs low without compromising on quality, that will tend to help them get more sales. 

So, how can they keep costs down? A lot of that comes down to efficiency in terms of equipment, process, supply chain, distribution, employees, and so on.

Past that, are they producing high quality paper that customers want? Are there any other services they can provide, such as printed letterhead or watermarks? Are they able to reliably meet their commitments and stick to their contracts?

Paper is in some ways a simple product, but all of those factors matter just like they would for any business.