I think you are going to be seeing soon that IOC and Clements are going to have very similar taxonomies soon, especially since there has been a bit of behind the scenes changes at IOC.
ALSO, re: research being free: HBW was for the most part not a source of original research, just a condensed summary of it. Now, a lot of that research is locked behind a paywall, which I something I dislike as a researcher myself. If I am paying a journal to publish something, why is the journal then turning around and charging people to use it? Especially when I am using grant money, which probably came from public funds, to pay for it.
Also I can't help but feel birders have it super easy, with multiple free world checklists that are updated annually, as well as several other easy to access resources (like this website). I have been trying to track down changes in reptile or mammal taxonomy, for my Covid lockdown list revisions. Most of those checklists may only be updated once or twice a decade, and some are horribly arranged with no clear indication of changes. Going through and having to do a genus level search in google scholar for all North American herp taxa just to figure out what new species and taxonomic changes have appeared is incredibly time intensive, and its still easy to miss things.