Pfft, give me a break.
I bought my Core i9-7900X about 2 weeks before Threadripper officially became available for about £850. Today on Amazon, Scan and Overclockers they are all at the same price if not more, so no it hasn't. Threadripper hasn't even made the slightest dent in Core i9 pricing and Vega 64 is only marginally cheaper (about £50) than a 1080Ti ... IF YOU CAN EVEN FIND ONE IN STOCK!
I'm deliberately comparing top-end products because everything else should fall in underneath that.