It's not really about "limitations" of the hardware, so much as it is about the fact that things have crystallized a lot since the 90s. There are no longer any mainstream architectures using big-endian integers for example, and there are zero architectures using anything but two's complement. All mainstream computers are Von Neumann machines too (programs are stored; functions are data). All bytes are 8 bits wide, and native word sizes are a clean multiple of that.

Endianness will be with us for a while, but modern languages don't really need to consider the other factors, so they can take significant liberties in their design that match the developer's intuition more precisely.