That may be one reason why Bangladesh and Sri lanka teams are down and out these days. But we will not see any support from big 3 for such small boards. PCB for instance, is undergoing huge financial crisis but recently NZ and ECB cancelled there tours despite knowing this financial crisis. Small boards have to do themselves to uplift there teams, don't expect anything from ICC or from big 3.
I agree that the ICC fund distribution is not being done in a fair manner. It is being done in a way to make rich boards richer and poor boards poorer. For the 2015-23 cycle, the BCCI (richest board in the world) will receive almost 5 times the funds when compared to the poorest boards like Ireland and Afghanistan. But it is till an improvement. During the Pawar/Srinivasan era, the BCCI used to receive 50 times the funds when compared to Cricket Ireland. They are yet to decide on the distribution model for 2024-32, but I hope that it will be done in an unbiased manner.