I think it goes beyond LLVM, it's software in general. 20 years ago, software was locked into a particular architecture because proprietary compilers and binary

I think it goes beyond LLVM, it's software in general. 20 years ago, software was locked into a particular architecture because proprietary compilers and binary blobs were the norm, and vendors still ruled their platforms with an iron fist. But nowadays, open source libraries and compilers are a lot more standard, and a lot of hardware/software is cross-platform so switching is easier. Linux is mainstream and gives you support for dozens of architectures for free. Also, CPU technology (outside of tiny embedded chips) is a lot more uniform with fewer weird variations or cost-cutting shortcuts, and transistors are ridiculously cheap. You can assume 32/64-bit, little-endian, twos-complement math, IEEE-754 floats, etc.