That’s why you need to define the term. Here’s the first result I got when I searched for a definition of capitalism.
An economic system in which the means of production and distribution are privately or corporately owned and development occurs through the accumulation and reinvestment of profits gained in a free market.
Can commerce occur in other systems? Of course it can. It has, it does, it will continue to do so.
Yes, some people will try to twist any type of system to benefit themselves. That’s true, and it’s also true that capitalism celebrates those evil motherfuckers, whereas some other forms of government don’t.