Cover letters are antiquated

Cover letters feel like a waste of everyone's time. What are companies hoping to find in cover letters?

1. I imagine the original purpose of cover letters was to help mailrooms figure out who to direct applications to, but that's no longer relevant when most applications are completed online.

2. In theory cover letters introduce a barrier to entry, which would improve the signal to noise ratio. But, in the era of search and replace this seems unrealistic. Applicants just search and replace company names in their cover letters, particularly when companies are in the same industry.

3. Cover letter serve as short writing samples. But, if companies are interested in evaluating writing ability, they should just send relevant written assignments to applicants who pass their initial screen based on their portfolios, references, and/or resumes before they offer them interviews.