I think you’ll discover you’re quite mistaken. The brand standard today isn’t the same as that of 20 years ago when some older hotels were built. But again, newer hotels always are nicer than older hotels. As I previously stated, Asia has much newer hotels than N America and Europe, despite whatever differences in brand standard might possibly have evolved over time (particularly with Sheraton).

I am aware that many in Asia (and China in particular) and abroad in general perceive Sheraton as a much better brand than we do in N America. That’s because Sheratons abroad tend to be newer and better train their staff to better service standards. Regardless, very few Sheratons qualify by any measure as 5*. The most likely Sheraton to be 5* may be the Sheraton Grand Sukhumvit Bangkok, which coincidentally is actually a Luxury Collection property.

There similarly are few Westins that qualify for 5*—and those almost entirely belong in Europe, part of the old Excelsior Collection that became Westin properties. The Westin Europa & Regina Venice, the Westin Excelsior Rome, the Westin Palace Madrid, the Westin Paris Vendome (soon to leave Marriott under new ownership to become a Jumeirah), etc. Those are truly impressive hotels...but they are the exception and not even close to the rule.

I also think you may be confusing brand new and shiny with 5*. Those are two distinct quantities that I think you’re unfortunately conflating. A 5* hotel is one of luxury and luxury service. There is a reason that most JW Marriott hotels don’t qualify as quite 5* despite their supposedly being a luxury brand: their service is not to the 5* level simply due to room count and staff/guest ratios making that impossible. If that’s true for JW, I can assure you it’s just as true if not even more true for most Sheratons and Westins and regular Marriotts and Renaissances and Le Meridiens. They may be prettier and newer in Asia, and Asian service may be a bit better on average than that in N America and Europe, but the 5* service standard also is a bit better there in Asia, accordingly. New isn’t 5*.