Are they? The i5-10600K sells for $262. Its closest competitor is ryzen 3600/3600x, which currently sell for $172/$200 respectively. For $62 (33%) more, is it really 33% faster than AMD? There are lower tier skus (eg. i5-10500) that match AMD's pricepoint, but I doubt they match 3600/3600x's performance. At the high end, the i9-10900K ($488) is competing against the ryzen 3900x, which currently sells for $400 and has 20% more cores.
It's the motherboard prices that will make the difference. Intel motherboards are always super overpriced, and you have to buy a new mobo with every generation.
That and you also need to factor in the cooler. The consumer Ryzen chips all come with an adequate cooler, which can save you a significant amount over the Intel chips especially considering the extra heat output you'd need to handle.
Keep in mind that the prices quoted in the article for Intel are 1ku prices, I'd assume that the retail price would be higher unless Intel were doing some retail promotion.
Probably not but for certain use-cases Intel is just way easier and less trouble (building a Hackintosh with Thunderbolt 3 connections for a UA audio interface, for one). And yeah, not everyone has such special needs but some of us do even though we may have one or multiple "real" Macs at home.
That's because AMD prices in the article are from the corresponding processor release date, not today's.
The big price drops with the current generation did help a lot in getting their offerings up to par. But I'd worry that that might change if you factor in the extra cooling you need to keep these in turbo and the motherboard, where the cheapest Intel LGA 1200 I can find is $150 and the cheapest AM4 is $50.