PACER was designed in the early 1990s, before the internet was popular, i.e., when AOL was the internet for most of America. Indeed, PACER is probably as old, if not older than, most HN users.

It has not been upgraded since then, largely because Congress has not provided sufficient funds to the courts for them to do so (appropriations in the past two decades have largely been reserved for operations or for courtroom construction, but not technological upgrades. Much of the money from PACER access fees goes toward meeting the shortful in the operation budget, because Congress in its infinite wisdom has underfunded the federal courts for most of the last two decades.

(It's wierd that I have spent most of the last two days defending the American court system...)