Our take on this:
Whilst there are thousands of cryptocurrencies out there, out of which some are specifically designed for payment, why would someone like Elon Musk and Mark Cuban promote Dogecoin which wasn't designed for payment and has infinite supply support such a coin?
Elon Musk and Mark Cuban would have by now made a few millions or billions by trading in Dogecoin. Whatever Dogecoins they are now holding in their portfolio is probably out of the profits they made in trading Dogecoins. In other words, they probably have already recovered their capital outlay, and are targeting more profits by prodding more of their supporters to buy Dogecoin by promoting Dogecoin.
In the circumstances, if Dogecoin suffers a setback they have nothing to lose and the least to worry about but not their supporters.
Like always, greed knows no bounds.