I think there is some variability between the brands.
If we're talking about bolt rifles, the Heyms and the Rigby's are roughly in the same price range. The stock aesthetics on the Rigby rifles are to my eyes, more attractive. The resale value appears quite a bit stronger on the Rigby. On the double square bridge Rigby rifles, the integrated EAW pivot bases are a very high quality improvement.
Inversely, on the double rifles, the prices of both have climbed quite a bit in recent years. The Rigby rifles are largely made in Belgium which I think degrades some of the prestige of the Shikari. The Shikari rifles presently are VERY close to a vintage Rigby double rifle. The quality of the vintage is of course sublime, and they hold their value very, very well. The resale value of Shikaris is yet unknown because they haven't developed a secondary market yet. The shikari rifles are not authorized for monometal ammunition, a serious limitation for a modern-made double. The Heyms on the other hand are bombproof, incredibly reliable, and have decades of field experience to demonstrate their longevity. All of mine have regulated very well and I found them wholly satisfactory. I do not believe the Shikari is 1.5x to 2x the quality of the Heym, but they are 1.5x to 2x the price.
To throw a further wrench into the works, I'd add that I believe the Dakota Dangerous Game rifles can equal or exceed the quality of the Heym and the Rigby rifles for about half the price. They also hold their values very well.
Disclosures: I've owned Heyms several times. I've handled numerous Rigby rifles and will likely own a Highland Stalker someday in the future. I've owned numerous Dakotas. I've never owned a Shikari and I don't plan on doing so purely because I view dollars better spent on either a vintage British Double or a modern Heym.
My opinions explain why restaurants have menus, not everyone wants the same things.