I imagine you're referring to Austrian economics here, but much more mainstream economists believe inflation to be fundamentally about money supply as well. Here's (nobel prize winner) Milton Friedman, from Wikiquote:

"Inflation is always and everywhere a monetary phenomenon in the sense that it is and can be produced only by a more rapid increase in the quantity of money than in output. … A steady rate of monetary growth at a moderate level can provide a framework under which a country can have little inflation and much growth. It will not produce perfect stability; it will not produce heaven on earth; but it can make an important contribution to a stable economic society."

That's not so say that many don't hold the belief you have (i.e. that inflation should be understood primarily as price inflation, and monetary inflation is a secondary consideration). But it's not the only mainstream opinion.