Not all of them got removed for example my sanguine has artifice slot in i fact you can check it out on my profile because it's equipped

Bigger question as to why we can't have T5 exotics already.

Almost all the exotics from before EoF I kept the moment I saw that the Freebees from Ada-1 were non-Artifice and WORSE max upgrade stats, only a couple newer versions where the spikes were worth tossing the already too low stat versions I had. The bad part is the "higher" stat older ones even not Artificed still had higher stat numbers than the current ones. Not as spikey, but still better overall. High stat ones after Artificing end up 91-95 stat. Max of current EoF version of Exotics and the Class ones are 88 stat total with whatever +10 mod you throw on (I really don't think I've seen any above 63 before upgrading). It comes off as they were trying to get people to stop using Exotics as much as possible by focusing more on stat distribution with 4-set bonuses. But then hinder you with still wanting an Exotic Armor on because additional benefit, assuming the -20 stat vs Teir 4/5 (103 stat total max without +5/-5 setting) Armor as a counter to power.

It’s because they can re-issue with nxt big dlc. So ppl have something to grind again. And they don’t have to put in any development time but you still spend money