Well think of this: if you knew there was $100 million in a dufflebag of gold at the bottom of a pond, would you learn how to put on scuba gear and retrieve it?
Perhaps you don't have compelling enough reasons to do things.
I do need a compelling reason to do something. I can't figure out how all these people get through what they do without wanting to jump out their office windows, to be honest.
Is it fun/interesting? Can I make it fun/interesting? Does it make me or save me money so I can do something fun/interesting?
If the answer is no to all of these questions, I'm going to have a bad time. Unfortunately, I'm that simple. I've gotten better at number two over the years, though.
Scuba diving sounds fun. I'd probably do it for less.
Learn how? Almost definitely.
Actually do it? That's a lot less certain than you would expect.
I would probably start. Since this hypothetical is a pretty simple one-off, I might even manage to generate enough executive functioning to follow through.
What I can tell you for certain is that I am still very excited to work on a custom keyboard project that I started 4 years ago. I have all the parts and equipment readily available at home, and plenty of free time. I have not worked on it at all over the past 4 years.
I have a similar issue, I can find motivation to start something but then it spirals into other things.
For $100 million I would probably just learn to put on the scuba gear but for instance my mind would go to "I should make my own scuba gear". So for a personal project I start on something and decide I need something else, so then I want to make a tool to help me make that thing and so on. I think it's probably related to a shorter attention span so I'm working on that.