Say you buy a some platform to develop on. This will normally come with a toolchain and some libraries. The library was developed on LTS. Now you try and compile that and it doesn't compile. Woe is you. You can't just ask the seller because he just told you to use LTS so good luck figuring out why it doesn't work.

OK, so you've spent some time and figured out the problem - it needs this particular version of this obscure tool. OK. No problem, I'll just compile it myself. So after tracking down the source you download it and try to compile it yourself. That tool has it's own dependencies. OK. 10 recursions later (I hope you're keeping all this crap in a local dir and not just blindly overwriting your distro version!) and you compiled the tool.

make

Another library that needs compiling from source - see above. Repeat for each one and its dependencies.

make

Nope! Your python is too new! OK, fix the script to you use the correct (older) python.

make

Nope, GCC defaults have changed! You fix the makefiles.

make

Success! You've wasted a week of your time you could've spent working on your product.