Mmm, do you have some examples or sources to cite? I don't know where you're getting these ideas, but I've worked for many nonprofits and considered starting my own, so had to understand their legal and financial structures a little bit.
If you have to beg every 2 years for money or you go bankrupt, that is some terrible planning. Nonprofits are usually run like businesses, and have revenues and expenses like any other business, usually continuous. It's not like they fundraise every 2 years and then spend money the rest of the time. That's just not how it works. They have boards, managers, staff, salaries, etc. that they plan for day to day, like any other business, and their revenue streams are not limited to donations (there can be grants, sales, memberships, endowments, whatever).
Wikipedia, as an example, uses that bullshit to stir up a sense of urgency as a call to action, but they are actually doing just fine:
https://www.makeuseof.com/tag/wikipedia-millions-bank-beg/
https://www.washingtonpost.com/news/the-intersect/wp/2015/12...
You can also look at their Form 990s for a clearer picture of their financials; https://projects.propublica.org/nonprofits/organizations/200... (it's not FAANG money, but it's enough for what they're doing, and they get richer every year).
The reason typical nonprofits don't get rich is that you can't really "invest" in them via capital injections, because investors can't get a return. That's what makes them nonprofit. But nothing stops them from doing routine business activities to make money on a predictable, cyclical cycle -- not a lump sum every year. That Wikipedia thing is just a marketing gimmick, the same way many charities will use holidays or Giving Tuesday to beg for money, but that's not their entire income stream (or even most of it).
The choice to become a nonprofit is exactly that, a choice. They don't "have it bad", they just choose their mission (well, ideally) over profit. Of course scams exist and some are just tax havens or whatever.
There are also non 501c3 nonprofits, like churches or issue-based advocacy groups, that have their own funding structures (tithes, corporate affiliations, whatever). And nonprofits can and do have their own investments, their own funds, etc. that earn a return, but it just goes back to the org and/or its staff (as salaries and perks, etc.), not shareholder return.
Overall, though, for the most part the primary differentiation is just that they don't have shareholders/owners to give money to. Aside from that they are mostly just businesses with a bunch of small technicalities of IRS rules to adhere to.