It may be technically poor in your particular domain of operation, which you fail to elaborate on, but I think in the domain of operation it targets, i.e. servers with performance, it evidently considered good by a great deal of smart people. For example, it totally dominates the top500 supercomputers, is used by Google for their backend, by a large number (most?) hosting companies. This is primarily due to the overall performance characteristics being better (not some sub-benchmark where FreeBSD or Solaris or whatever pulls ahead by 1 or 2%).

That is to say, the Linux kernel is the fastest for general performance oriented server tasks. It may be the case that in some areas you can get some other unix-y operating systems to outperform it, and by all means use them in those circumstances for your projects, but I think your blanket unqualified dismissal of the thousands of kernel developers as being technically poor and ultimately "worse is better" is a bit over the top.