It's not just that the article misunderstands that unit tests are easier to maintain (if well written at least), but they also don't seem to discuss the problem

It's not just that the article misunderstands that unit tests are easier to maintain (if well written at least), but they also don't seem to discuss the problem of combinatorial explosion that plagues end-to-end tests. There are only two ways of avoiding that problem: ignoring it and simply give up on comprehensive testing, or realise that comprehensive testing can only be done by writing mostly unit tests.