This may sound counter intuitive, but you have far more to lose by staying than by moving on. In fact you face a couple significant risks that increase the longer you're there.
First, the founders may sense your lack of "enthusiasm" and realize that your chances of leaving are high. To protect the company's reputation from the public vote of no confidence implicit in your quitting, they may decide to take the initiative and fire you. Yes, this type of behavior is underhanded but it's more common than you may think. Imagine trying to explain to a hiring manager that you were fired because you planned to quit. Unfortunately, no one will believe you.
Second, you're part of a sinking ship and as the tech lead there's no way to separate your reputation from it. The longer you stay, the longer you expose your personal brand to the failure at large.
My last advice is the most important because it should guide all of your career decisions. Do not let fear suppress your better judgement. Step back from the reasons you listed for staying at the company and you'll realize that fear is the commonality. Fear isn't your friend. It will mislead you.
However, the bean counters and glad-handers who stand between you and a paycheck often ask difficult but irrelevant question, and if you don't worry about explaining yourself to them, you make it much harder to get that paycheck.
You get a lot farther with the ability to solve real-world problems and MBA-appropriate skills than with just the ability to solve real-world problems, if only because there is such high demand for technically inclined people with people skills and business skills.
First, the founders may sense your lack of "enthusiasm" and realize that your chances of leaving are high. To protect the company's reputation from the public vote of no confidence implicit in your quitting, they may decide to take the initiative and fire you. Yes, this type of behavior is underhanded but it's more common than you may think. Imagine trying to explain to a hiring manager that you were fired because you planned to quit. Unfortunately, no one will believe you.
Second, you're part of a sinking ship and as the tech lead there's no way to separate your reputation from it. The longer you stay, the longer you expose your personal brand to the failure at large.
My last advice is the most important because it should guide all of your career decisions. Do not let fear suppress your better judgement. Step back from the reasons you listed for staying at the company and you'll realize that fear is the commonality. Fear isn't your friend. It will mislead you.