Much of the common optimization in Windows can be achieved by being aware of what each installed component (applications & utilities) does to some areas of the registry. We can see and modify some of these influences through MSCONFIG and the Startup list that it shows - it takes some research to determine what each item does in the list and what the effects are in removing it. This effort is normally looked at as real work and therefore isn't very popular, as a result many people turn to the "snake oil drummer (salesman)" & buy the packages that profess great improvements to your system. There are also those that won't do the work and don't want to pay - they install all the freebees they can find and then wonder why their computer won't respond.
Other areas of optimization also involve WORK

This means reading about things like settings, file management, disk operations, etc and then experimenting with these cerebral discoveries.