You couldn't a week ago. This isn't some accident. Their openness comes hard won with threats of their reputation.
Their digitization is largely done by a for-profit company. It's not competitively bid. There are many parties who would digitize these works at no cost— archive.org and google for example, and could afford to do it without pay walling the results.
Anyone at all (including you) is free to scan journals that are in the public domain and publish them online for free. If you scan/ocr them then there are many places (including Project Gutenberg and archive.org) who will host them for you.
Their digitization is largely done by a for-profit company. It's not competitively bid. There are many parties who would digitize these works at no cost— archive.org and google for example, and could afford to do it without pay walling the results.