Windows 10 does have a build-in PDF reader - Microsoft Edge. Also Windows 10 includes the virtual "Microsoft Print to PDF" printer, so this issue isn't really much of a problem unless the user in question (who also runs Windows 10) is using some special features in the Foxit Reader's Print to PDF tool.
Tbh Microsoft should just have a built in reader for the 99% case of viewing documents and filling out simple forms.