Eh, not really, yes building really good speakers requires comprehensive knowledge of various subjects, but it's not rocket science, you don't need do emply hundreds of PhD level engineers like nasa to build speakers on high level.
There are some DIY builders who do stuff on genelec level and even surpass them in certain things. Take March Audio, isn't that a venture of one man? His speaker scores 7.0 on Olive preference score function...
Building things DIY is great fun but its a big waste of time and money . I can recommend it if its for fun and learning .
I have done this during a couple of years.
But at the end of the day, when your loudspeaker is finished and you want to move on to other projects and maybe try to sell your beloved DIY speaker - you will loose money because the second hand value are nonexistant no matter how good they sound .
Its important to have a reference loudspeaker to listen to when you develop your DIY loudspeaker . I borrowed a Genelec 8330 , did extensive measurements and listening tests during a weekend only to find it was impossible to better the sound with my own DIY HYBRID dsp loudspeaker . Ofcourse my HYBRID did sound better than jbl 305 ( my other reference ) but thats a very cheap loudspeaker.
March audio is no DIYer , its a professional small company. I guess the owner have been building loudspeakers since he was a kid .