Sony has nothing to do with this any more as "in May, 2016, MAGIX acquired the VEGAS Pro and VEGAS Movie Studio product lines, along with other video and audio products".
Since then the Vegas product lines come from MAGIX.
Note that the Steam Editions of those products have some restrictions, e.g. you cannot have two instances open simultaneously. And they do not currently entitle to a future upgrade pricing in the Magix Vegas Store.