Can you elaborate on what you mean by "rely on proprietary renditions within one version of a brand of software"
Corel and Adobe ( and likely others ) have some features within their software that allow you to do 'fancy' stuff on your vector art.
Problem being, these effects should be rasterized at scale before sending the file out, as they rely on the specific program
to render the effect properly. Heck, even thickened outlines don't always translate properly between formats.
It's nowhere near as bad as it used to be, but it's still something to keep in mind.
Maybe 10% of all art jobs that land on my desk have a 'proper' vector file, and those are just a simple logo with text.