Great work. I would love to transition to a model that you've done with invoiced!
p.s. Small typo on your 'Features' page, 'inforamtion' instead of 'information'
The misconception about what a 'founder' represents is so true. I've been guilty of it myself till I spotted the danger signs (delegating too much, modelling myself after Steve Jobs with the misconception that all I have to do is have 'vision' :P).
The reality is as a startup founder, you're expected to bear the blunt of the risk as well as majority of the tasks, from getting coffees, to setting 'vision', to product design, and coding the mundane that others don't want to do.
To this day, I still firmly believe that (on my 1st startup, so additional mileage may change that) having a diverse skillset, or the uncompromising willingness to learn anything is key to success - guess that's what PG calls determination.
So going back to the OP's view that solo founding is possible - I totally agree. You may need to hire or get help where your tech / business skills are lacking. But if you have sufficient & diverse work experience, and some financial capital, it's totally feasible to go solo.
A big BUT is the emotional support that a team can offer. This is even more so when you have a solid co-founder. The trials of startups are hard and deeply emotional (I think all founders will naturally develop bi-polar disorder - one day you feel on top of the world with your world changing idea, the next you are filled with doubt), so any kind of support from people that understand what you're going through helps - this is unlikely to be your spouse if they've never been exposed to startups or even the financial burdens of brick-n-mortar business. You can substitute with meetups and surround yourself with startup founders, but someone who doesn't have skin in the game just isn't the same.
TL;DR So while I think it's possible to do it alone, there are added benefits to being able to share the responsibility & emotional rollercoaster of a startup
I also recommend everyone read 'Founder's Dilemma', good data backed analysis of pros & cons of various startup decisions like solo vs. co-founding. Bootstrapping vs. funding, etc.
Too bad the company got bureaucratic. But it seems to be the nature of things. Startups are born, they grow, they get big, and inevitably they get boring because 1) maintaining legacy code & doing incremental changes is never as fun as green-field development 2)having customers mean proving you can be reliable, and that comes with doing hard work - providing customer support, fixing bugs. Snazzy new features give way to doing what the market wants.
I'm glad you made the leap to quit though, because it does sound like you were genuinely bored. While I agree a life guided by curiosity and experiments is the right pursuit, I personally don't think that luxury will always be available to us ALL the time. Sometimes, we just have to put up with doing boring tasks...