The amazing thing about America is that there are paths for those not as wealthy, but of course they are harder, as much as we might not want them to be... no?
The US is not special in that regard, and in fact not even particularly good at it.
America is 100% the place to be rich or poor, if this really is your goal, from Dolly to Jackson or Swift.
Did you hear about this little band called the Beatles?
It is, but people often act like it isn't and everybody has an equal chance. Therefore it is necessary to frequently restate the obvious.
Nobody is claiming this or ever should. The claim is that there is real proof of "success" from dirt poor to middle|upper class with these music entertainer examples. Nothing ever will be equal chance, and that shouldn't really be the goal [depending on how it's defined and implemented].