A lot of this is pretty normal when you have multiple big companies with talent moving back and forth and taking what they feel is the best overall offer to what they want out of this profession.
It wasnt that long ago that AEW successfully out bid WWE for Mercedes, Okada and Ospreay.
There will also be young talent from the WWE side that will probably jump to AEW over the next few years as well since there won't be room for everyone and some of them will believe they have a higher ceiling then how they are booked.
What's actually a talking point is how all the rest of the wrestling companies have seemingly turned into feeder programs for WWE and AEW.