CashApp was launched in 2013, long before Zelle and other instant payment rails arrived, which closed wallet providers solved for (Venmo too, owned by...Paypal). There is little growth to be had when these customers can get free deposit accounts with access to Zelle or FedNow to move value for free instantly. It's success to be sure to accumulate the cashflow from the customer base built, but it isn't lasting.
It also solves an exclusively American problem. In my country anyone can send money bank to bank, no need for a separate service.
It's a US only problem.
Everywhere else has instant settlement payment rails available for yonks.
And FedNow removes the need for Zelle or CashApp, assuming the banks offer it.
Of course, a regulator working for the consumers might mandate as part of a banking deposit taking license, that the bank must offer FedNow as part of the account at zero transaction cost to the account holder, perhaps with transaction limits.