1) Within the United States, the largest corporations are closely associated with government, with a very porous interface between their highest levels. And they certainly aren't always allowed to fail.
2) Once a megacorporation has established dominance in a given market, a combination of network effects and regulatory capture removes competitive pressures. This allows the internal planned economy of the corporation to continue without competitive pressures. See e.g. Google, which essentially throws money earned through dominance in ad markets against the wall in every direction but produces little of new value.
The reason my "capitalism" has quotation marks is to point out that actually existing capitalism in the USA has pretty much nothing to do with competitive free markets.
2) Once a megacorporation has established dominance in a given market, a combination of network effects and regulatory capture removes competitive pressures. This allows the internal planned economy of the corporation to continue without competitive pressures. See e.g. Google, which essentially throws money earned through dominance in ad markets against the wall in every direction but produces little of new value.
The reason my "capitalism" has quotation marks is to point out that actually existing capitalism in the USA has pretty much nothing to do with competitive free markets.