Being able to recognize a brand is necessary for the market to function. It is how you know what you are buying, and what you base trust on. At the same time, the cost of coming up with a different name for your competing product is trivial.
So while, yes "the same applies", the cost/benefit ratio of the two situations is totally different.
And one of the tests in trademark law is if a reasonable person would be confused between the original and the imposter. So you only have to have 'reasonable' knowledge of other brands in your industry.