Regarding Thiel's demise, there are different ways to look at it. Jim Thiel was a genius and he doggedly pursued his vision for phase and time coherence in spite of technical challenges that most speaker designers feel are insurmountable. He did not have an understudy nor did he have a team of engineers doing most of the work. When he died the company pretty much died with him. According to his brother, Tom, they tried to find someone to replace him but were unsuccessful. The new owners tried to steer the company in a new direction but couldn't make a go of it.
There's an anecdote that has Jim talking to a major high end speaker manufacturer at a trade show and he's reluctant to discuss an idea because he hasn't patented it yet. The other executive laughed and said something to the effect, "I don't know why you waste money on patents. Nobody is going to try to copy what you do. What you are doing is impossible."
High end audio speakers are an extremely complicated component with difficult tradeoffs. I would dare say that most successful high end speakers are the result of one person's vision. David Wilson was fortunate to have a son who was capable and interested in taking over the design process of their speakers. Jim Thiel was not so lucky.