If I am designing an e-commerce site for a new product that cannot be protected with a patent or copyright, how to I protect my concept from copycats?

Move quickly and build a brand. Leave them a step behind trying to copy you while you define the market.

You just answered your own question by admitting you can't "protect" your product from copycats. So just accept this and don't worry about it.

A copycat will always be a step behind. They can copy what they see on your site, but will never understand your thought process or customer learnings that inform your product decisions.

I have never (ever) seen a company fail due to copycats.

Focus on 1) Delivering an awesome experience to your customers and 2) Finding as many of them as you can; and you'll do fine.

Happy to discuss in further depth on a call.

There are other types of intellectual property protection beyond patent and copyright... But you might be better off just using your 'first to market' advantage. By definition copycats are not as good as the original and in a sense they could help you by highlighting your strengths. But you do need to make sure you are always ahead of them. With current apples of business they might outrun you and take over...

Most great ideas come from something that already exists, and we tweak and refine it to make something better. Instead of worrying about the potential copycats, focus on the new product and how you can get out to market with a very friendly e-commerce site so people can purchase it quickly.