"...... Speaking of the decision, Iain Rawlinson, who is a member of Sentebale’s board of trustees, told the Telegraph: "These polo games, which attract great generosity from high-net worth individuals or funds who want to support the charity - those events definitely have their place. We’re not being critical about that as a concept.The reason for [dropping it] is it puts quite a lot of pressure on individuals, and it can mask structural weakness in the financial model of the charity."

"...He then cited Harry’s £1.2m donation from the proceeds of his memoir, Spare, as masking "the fault lines in the financial model which had really been producing losses since 2017".

In other words, Sentebale was on it's last legs for quite a while. I know that US donations dropped by over 50% in the first year Harry and Meghan married. The donations never recovered and attendance at the polo matches dropped to nearly zero. Harry's "donation" from Spare still wasn't enough to cover all the costs and I'm sure the people at the top, including Harry were skimming the money for their shares.
The charity was a financial bust and I'm sure there was shady activity going on. I hope the charity can recover now that Harry and the other people involved have departed.



https://www.express.co.uk/news/royal/2117010/royal-family-live-prince-harry-sentebale-row-polo