Well actually Wizards of the Coast put out a Prestige Class in Unearthed Arcana back in 2015, along with experimental guidelines on how they're constructed in 5th edition. So it's more like WotC dug them up :)
And abandoned it like it was the plague. Its 5 years ago. This UA came out 1 year after the release of fifth edition to see if there was intrest in prestige classes. There wasn't, and probably isn't, because sub- classes are filling this niche.
That being said, I haven't read whatever you made, so I'm not sure if that's good or bad, I just wanted to reply to that statement.