[dtech]

The point is those optimizations are not here now, and haven't been there for the last 25 years. Hand-waving them away as theoretically possible is dishonest. We're 25 years into the most popular programming language's lifetime and the most advanced VM available only recently learned good escape analysis. It isn't easy.

> which, I'd be curious to see how .NET supports an array of struts (that are presumably changing over the lifetime of the array) that is allocated as a global.

Very easy. An array-of-structs (which can still be on the heap mind you) will just be a continuous block of memory. This is totally independent of any locking and synchronization.

For example in a class with 2 32-bit fields, and an array of objects a b object-ref array will look like: [p_ap_b], p being a pointer to [a_0a_1] or [b_0b_1]. A struct-array will look like [a_0a_1b_0b_1].