Many proprietary operating systems are designed for the lowest common denominator. Only. This makes doing anything constructive with them an uphill trip in both directions. Even if you spend money on a compiler which runs under those OSes, do they include strace ? How difficult is it to chroot before executing a process? What enhanced security facilities (like Mandatory Access Controls) can you apply to an individual process? Where is the setenforce command? Most users don't even know what these things are, let alone whether their OS has them, which for the majority of cases is just fine. They don't need to know, For people who do know what these things are, their absence can make life Hell (even if only in limited situations & for limited times, nevertheless Hell). In the case of F/OSS-style software, they're included because the people who use the software wrote the software. EVeryday users don't even need to know that these tools exist. Simple?
Linux Advocate in Western Australia