If you had never seen a car before and were blind to marketing - I don't think someone would sit in a BMW 5 series or a Mercedes E class and think they were any more "luxurious" than many mainstream vehicles. Both the 5 series and E class would be a step down in ride comfort and NVH from a Ram 1500 Limited. Yes - they are a bit less expensive than the truck. But in the same ball park. The lines have gotten pretty blurry to the point that I'm not sure there is much real world difference anymore. Mostly marketing. At least as far as the common models go. A Lexus LC500 is a stand out vehicle. As is Mercedes AMG GT. Maybach. Probably the LM probably would stand out as ultra-luxury. But not the normal stuff.
I do think Lexus should include all the typical features available on a top trim Toyota as a base model Lexus. That's the general idea - Lexus steps in at the top of the Toyota range and carries on up the trim levels from there.
The biggest deal breaker for me is the 17mpg. I believe the numbers released are 15/21/17 mpg. Not great for a midsize SUV.
I do somewhat agree with you. I think if you compare the top trim of many mainstream vehicles versus the base trim of a luxury vehicle, often the top trim mainstream vbehicle is going to seem just as luxurious or more so than the base trim of a luxury vehicle.
When you start to move up to higher trims and options offered in some of the luxury makes though, I do think you can get a much nicer overall package often, but you're going to pay A LOT for it potentially.
For example, part of me is seriously just settling for something like a Hyundai Palisade Calligraphy to replace my Rover. I'll end up with more features probably in it for $53K than any luxury vehicle south of about $80K.
If you look at some of the upgraded optional interiors in mid-tier and up vehicles from Mercedes Benz or Land Rover though, they often are blowing the mainstream vehicles out of the water. I don't know if you've seen a current 2024 X5 post refresh; especially with the leather interior it's nicer than anything in Toyota's lineup by far in my opinion. Lexus, probably not...
On the G550, I do agree the 17 mpg combined is pretty bad. But if you compare it to some similar vehicles (larger SUV, 8000 pound tow rating), the Defender is rated 18 mpg combined, the Tahoe at 17 mpg and the Seqouia at 20 mpg. The real outlier is going to be the LC250 with that Hybrid powertrain assuming it ends up rated somewhere around 25 to 26 mpg.
I'm lucky if I get 16 with my 4Runner in real world usage here, so I guess it just doesn't bother me that much, especially if I end up with something more efficient as the other vehicle in our garage.