No, that's not it.
Take something like filing taxes. The tax laws are very arcane and convoluted. And yet, we can take something like TurboTax that (if we disregard the upsell dark patterns) can make the average joe competently file their taxes. It has wizards to guide you step by step, it will hide crap that is not relevant and not even prompt you for it.
On the other hand, there are some countries, like Brazil, with their own government supplied software. Compared to TurboTax, they are a nightmare. There is zero guidance on what you have to do, they have all fields you may ever need in any tax situation in your life. The only thing it does competently happens when you press "send". That, and importing older returns (kinda, sorta, provided you have explicitly saved the old backups in the correct format, or you have last year's version installed).
> very few companies have the billions of development dollars the above handful of companies have to throw at the problem to try to make it tractable.
Sorry, all I hear is a bunch of excuses. You don't need to have billions of dollars, all you need to massively raise the bar is to have a UX team – or frankly, a single UX person that is listened to and is able to engage with actual users.