Witch Bolt - The Emporer Strikes Back

[Gadget]

And since Enervation came first, then the mechanics, as written for 5e, are first applicable to Enervation...not the other way around. Something that objectively comes "after" [i.e., the Witch Bolt spell which they, I'll take your word for it, modeled after the mechanics they rewrote for Enervation in 5e] can not be taken as the thing that "came first" [i.e., Enervation which has been a spell in D&D since 2e].

To suggest one does/it can is...as pure an inversion of logic as I have ever seen. You are correct that 5e is very "tight" in their verbiage. Things that do the same (or even similar) effects are going to have/use the same phrasing. That, in no reasonable way, translates to 'so, they based Enervation off of Witch Bolt.'

Have you read the spell? It is very obviously based on Witch Bolt. If you cannot see that, I cannot help you. Witch Bolt came out first, in the PHB (published August of 2014). Enervation was only published last fall in Xanathar's Guide. That other editions had a spell called Enervation is irrelevant to the point. The mechanical implementation used in 5e is new and unique to these two spells. They very much did base the implementation of Enervation in 5e off the mechanics they invented for Witch Bolt.