That's true to some extent, but mostly for military equipment and guns. For everything else, there's much more room for a new corporation, especially a player-run one.
Some questions for it are:
- What nation would it be based out of?
- What's it selling? (e.g. your niche)
- Who's it selling to?
If we can answer those well, I'd say go for it. Here's the
guide to being a merchant on Star Army. This a pretty recent guide so I'm looking for feedback on it from people who use it, so let me know if you have suggestions.