Don't think of them as the same picture. Think of fascism as what capitalism will become. The monopoly game starts with people buying land as fast as they can and ends with screaming and the board being thrown across the room.
I might have the wrong definition of fascism, but I typically think of it as extreme government overreach and control. Capitalism, however, needs a free market and free-will exchange, both of which government restrict.
If you wanted to argue that capitalism inevitably devolves into fascism you might be able to, but I suspect that any economic system would just as easily devolve to fascism.
In order for capitalism to devolve into fascism, you'll have to corrupt the government (otherwise there's no way to override free will exchange). However, what exists in capitalism that makes this easier/provides additional incentives for this? Every system with a government will have powerful people who want to manipulate the government for more power.
From Wikipedia:
Fascism is a far-right, authoritarian, ultranationalist political ideology and movement, characterized by a dictatorial leader, centralized autocracy, militarism, forcible suppression of opposition, belief in a natural social hierarchy, subordination of individual interests for the perceived good of the nation and race, and strong regimentation of society and the economy.
The only part that could vaguely be associated with capitalism (in a democratic country) is "militarism" and even then this is only the case if you mainly focus on the USA. The fact that fascist countries were running free-market economy is also not really a point since that was (and is) the case for a large part of the world.
"subordination of personal interest" and "strong regimentation of [...] the economy" is the opposite of prototypical uncontrolled capitalism. Saying that capitalism is fascism is just as stupid as saying that fascism and socialism are the same ("bUT it wAs cALLed naTIOnaL soCiaLIsm"). Using the word "fascism" for everything you don't like just makes it lose all meaning.
Difference between communists and Nazis is that one of them lost a world war.
