They seem to be trying:

> In addition, arXiv will provide substantially better access to the visually impaired by producing HTML as well as PDF versions of its content.

But it's a different question whether they will succeed. A compile-to-HTML pipeline needs to work with every single LaTeX package that people use, or at least work with most ones and fail gracefully for the rest. That was hard enough for compile-to-PDF, requiring the arXiv to keep every year's version of TeX Live permanently maintained.