They can become a problem, I believe, if market logic becomes the dominant mindset by which things, or also people, are evaluated. (Market logic = attaching an exchange value to things, including labour, land, people, nature, art)
I believe markets, even farmers markets, are not "of the commons", insofar as there's usually a high degree of trust and knowledge between the members of a commons, so there's not a need to attach monetary value to anything. – If I think of traditional commons like those managed by the English peasants, they just rotated the fields among each other, didn't they? (there must have been a variety of practices). Or the cows being made to graze together in the Swiss mountains, there is no money exchange there? I imagine you could have a membership fee to be part of a commons. But not usually a market within the commons.
I wonder if it might not even be a key characteristic of a commons that it can happen without money.
In a gift economy, you do some kind of accounting in your head, and in a LETS scheme you have explicit accounting. So, there's a gradual move towards attaching an 'exchange value' to goods or services. But as these communities are small and there is still an element of trust, it is really more to keep track.
If you start to directly compare things to each other ~ attaching a value that you can measure in units of accounts – something changes profoundly. As the number of participants grows, it will eventually drive competition of the kind where people have to become more productive to keep up, and might eventually feel the need to cut corners.
Competition is good if it's for quality; if I have the ambition to brew the best beer, to take an example of yours. But if my ambition is to beat my competitor on profit, that changes things. I think it would be perfectly possible to have just one brewery in a village and still have good beer, as usually people do want to create a good product. They will want to drink their own beer I guess! They could make a variety of different beers.
Our society is so suffused with market logic that we take it for natural or necessary. And yeah, for your laptop it might be necessary. But not for most things people do, and the things that are truly valuable in life.
To answer the originai question, I think 'marketism' is a good term, and I would equate that with an excess of market logic.
