Yes this is the crux of it basically.
I can't help but think that Meghan saw Harry's surroundings and the pomp surrounding the royal family and incorrectly assumed that Harry was rich and famous. I think she overestimated the wealth factor.
But the rich element is not on the scale of American A listers who have had a successful career with hundreds of millions in the bank and a constant revenue stream.
The only continuing revenue stream that Harry had when she met him was via his father for being an active and working member of the royal family. Upon opting out of doing the work of an active British royal in the UK that revenue stream ceased understandably.
But to have a revenue stream on a continual basis you need to be selling a product, service or yourself with talent - ie actor, musician etc. etc. This is where they just haven't thought through a proper strategy. He's not going to just be paid mega money for being Prince Harry in America without actually doing something for it.
Yet their lifestyle eats up masses of money year on year. Even his inheritance would be swallowed up in time paying for the lifestyle. So how to generate money?
Well once you've done the gigs of selling out your family for money that also tarnishes you as it's not very pleasant or edifying. Once tarnished your "stardom" diminishes and your earning potential decreases as well. The cycle downwards.
You would need clever and constructive guidance from top pros who know what they are talking about. But here again I don't think H & M like listening to constructive advice. So it's tricky all round and will only get worse with time.