Windows 10 does fully support installation and use of Type 1 fonts.
What do you mean by “the fonts wouldn't load?” To install Type 1 fonts on Windows 10 (and all previous versions of Windows since Windows 2000), you place both the .pfm and the .pfb file associated with each Type 1 font into a single directory. Right click on the .pfm file and select Install for all users. That will copy the .pfm and the .pfb to the proper location and set the registry entries for the font. Restart your application(s) and the Type 1 fonts will be available.
That having been said, newer versions of Microsoft Office (since at least Office 2013) don't recognize and support Type 1 fonts at all. For those applications, you must use either TrueType, OpenType CFF, or OpenType TrueType fonts.
- Dov