The exact legalese preventing or enabling this is unclear to me, but if it became a norm then basically every for-profit startup would likely start out as a not-for-profit taking advantage of all that offers and then segueing to for-profit when big investment/sales opportunities emerge, and at this point we're making a mockery of everything these classifications are supposed to stand for.
Then plot twist, I turn the non-profit for profit, I avoid releasing the cancer cure I promised and instead I charge you for cure.
If a non-profit promised to cure cancer to help citizens, I would want that at the very-least they remain non-profit.
A peculiarity of US law vs others is it follows letter-of-the-law vs spirit-of-the-law. When there is ambiguity that billionaires try to take advantage of, it helps for legislators to pass laws rather than leave it up to judicial interpretation.
This is not close to true. The US legal system has many bizarre quirks (like elected judges, elected prosecutors, and a politicised judiciary) but this isn't one of them. It is a basic requirement of the rule of law that statutes are construed from their text, and not given meaning based on what judges wish their text instead was. People have the right to be able to have some level of certainty about what the law says.
The issue is when there is ambiguity. Judges must then make their own interpretation, and things get murky. In the US, spirit might be used in a hybrid spirit/letter in practice, though ultimately still grounded in literal text. Either way, my point was the role of people in dealing with ambiguity largely goes away when the law gets updated to be clear. Roe v Wade is a popular example of what happens when lawmakers fail to legislate and leave the law up for grabs.
RE:"Rule of Law", most of Europe is heavier on spirit-of-law. Both the US & EU systems seem historically strong on rule of law, irrespective of their stance on spirit vs letter. I'm not in a position to say being on one side or the other disqualifies a system from being a valid rule of law, that sounds extreme.
There was no legislative gap, by the way. Nobody failed to legislate. There were bans, or not (it was legal in some, and for different reasons) at the state level. Everyone understood states to have the ability to set their own criminal law, with relative freedom. Then "substantive due process" (not in the text of the constitution) came along and a group of judges decided abortion bans weren't in the spirit of the law.
The practice in civil law systems, as I understand it, is that the role of precedent is limited and statutes are more detailed and updated more frequently. In common law systems, statutes tend to be less detailed and judges fill in the gaps--so which of those sounds to you like it focuses judges on the letter of the law and which on the spirit?
RE:Letter vs spirit, the EU interpret statutes more flexibly, even if they're more detailed. In the US, judges do fill gaps (e.g. precedent), but are more rigid in applying the letter when clear. That literalism extends to precedent too. E.g., they rather pedantically follow a past interpretation rather than make a new one.
That literal predictability makes it damning for US legislators refusing to legislate. If Roe was clear via federal law, then US judges either have to follow it literally or declare it unconstitutional, and there's little room inbetween. In the EU, judges can more easily go for the spirit.