To my knowledge there is no function that would allow dynamic conversion of the displayed topic to PDF.
After clicking print you can set destination as "save as pdf" if you have any pdf writer software or plug-in.
If you have Adobe Acrobat installed on your machine then you must be seeing this option or else there are some free pdf writer plug-ins also.
Yes, you are correct; however, a competitor's product does offer both the Print button and a PDF button. Since my WebHelp product from 2012 contains PDF links, I did not want to remove this functionality but perhaps make it more readily available.
Your mileage may vary. But if you want to create a PDF, why not generate one with RoboHelp and add that as a download to your help?