Because everyone knows a Lexus is just a dressed-up Toyota.
The logic gets fuzzy when you consider the the VW MLB and later MLBEvolution platforms are used in a wide variety of cars from a humble VW to the upcoming Lamborghini Urus, not to mention the Bentayga. Lexus did use mostly Toyota parts years ago but they've moved away from that. People buy a Lexus because it lasts and holds its value. I've been a longtime Mercedes buyer and current owner, and also own a Lexus, and in the process of ordering another Mercedes. In the same realm, people who buy a Maserati are just buying a gimped Ferrari because they couldn't afford anything better. Or people buying a Lincoln are just buying an overpriced Ford. People buying a Land Rover or Jaguar product are just buying a mashup of hardware and control surfaces, because they couldn't afford better. People buying a top package Camaro pushing out 650+ HP couldn't afford the Corvette ZR1.
That said, the only true fact is the highest end Lexus, discounting the LC, is the LS, and when loaded it'll be over six figures. It looks nice, apart from the Predator grille, and apart from that as well, it'll last 20 years if taken care of and it'll still hold value. Meanwhile a new S class will drop 50% of its value in 4-5 years, and bottom out at around $10,000-14,000. Servicing a Lexus is 'cheap,' for odds and ends, but any serious work is going to cost you as much as a European import.
That said, while the new LS is quite nice, it's no match for the S Class. The BMW 7 series is also a stunner, but it's not a great match, especially with BMW's recent actions regarding CarPlay. I won't even count the Model S as a competitor. A 2007 E Class looks nicer inside.
Fact is, Samsung (or rather Android) buyers want something else other than an Apple product, and people buying an iPhone product want a safe product and one that'll work, and won't quickly become outdated with the next gen Qualcom release. It's comparing apples and oranges.
I use a Samsung S8. My work phone is my old S7. My wife has an iPhone 8 Plus. iOS is cool, but it isn't for me. I find Android easier to use and more intuitive. And I can tinker with it. I don't honestly think Samsung could ever satisfy the wants and needs with their flavor of Android to get hoards of religious iPhone owners to migrate over.
This argument is akin to the pc vs. mac debates from the 90s and 2000s. Use what you want to use and makes you happy. Who cares what the other person is using? Arguing over the matter is fruitless. We'll all be dead one day and none of this will matter.