It's true there is a bus to Marin every 20min but it uses a _single_ fixed route. People that live far away (>1km) from this path spend less time driving to Pontevedra than walking to the nearest bus stop.

It is not just increasing frequency, it is a matter of providing alternative routes to serve an important part of the population.

You could also bicycle to the stop? It's not really practicle to cover any rural location 1km apart with a bus stop.