- the firm asks for more money - people pay the price
That requires people with money prepared to pay the price and a lack of effective competition from other suppliers for that money.
Which this all shows is that firms mark up costs and try and get as much for their output as possible. What keeps prices down is that people can usually go elsewhere because there is excess capacity to supply. We lack supply capacity at present.
Inflation is therefore down to a lack of competition. The solution to that is to encourage more firms to start up, break up existing monopolies or forcibly create some.