[jasode]

>I hear they generally are "freely" available, just email the authors and ask.

I didn't downvote you but the way contracts work, the researchers are not allowed to share the final published article that was professionally edited and typeset by the journal. What they can legally share are the preprints and manuscripts.[1]

Yes, some researchers may ignore the contract they signed (wink wink) and share the final published pdf. IME whenever I asked for a paper, I got the preprint -- which means the author honored their publishing contract. The preprint is fine in most cases because it will have the main idea of the research. However, it's often missing the pretty graphs and illustrations that the journal adds.

[1] https://www.elsevier.com/about/policies/sharing