Question...Why can't there be a hybrid CPU?

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Hi,

Totally new here so apologies in advance if I've done something wrong with my post.

I'm looking at building a new PC, still rocking a 2600k and it feels weird having the same computer for so long, so... I've been researching 1950x for the multi tasking for 3d rendering etc but I also use After Effects and Photoshop a lot and that is better with single core performance, say a 8700k, so in the brain drain of thinking which way i should go I have this noob question:

Why can't there be a serious multicore CPU like the 10 core i9 or 1950x that has 1 core (the first one) which is like a 8700k in terms of performance, with the others being lower as per the normal versions? So in single core software or games it's fast but when you need multitasking the others kick in and the first one maybe even steps down to equal out?

I'm sure someone who know's what they are talking about will answer this and make it seem obvious but goddammit I want intel/AMD to make it happen so I can stop changing my shopping cart and just buy something!

 

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But is there anything technically stopping one core being hypothetically, a killer 4.8ghz all the time and the other 15 were 3.4ghz for example?

 

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Would it not be existing cpu's just configured together (obviously quite a bit of R&D to merge them but it's not alien tech) but those cpu's would still be available separately. Adding a relatively low cost 7700 chip with really good single core performance for adobe suite, games etc, at normal temps, merged with existing multiple 10,12,16 core tech. Most of this stuff at the higher end is niche already in general terms but i'm sure most people at this higher end would want this as it covers all software bases. In my dreams this all works perfectly...maybe if I click my shoes together and wish?...