I loved boarding school, and was very happy there. Some of my siblings went, and others went to day school. Of the 7 of us, my parents always say they spoke to the ones at boarding school far more often, and in more detail than the ones at home, so I am not sure where you get the idea that boarding means a wholesale outsourcing of all parental responsibility.
While the average teenager slouches home and spends the entire evening closeted in their bedroom, we were far more likely to take the time to call home and see how they were, and talk about our day.
20 years on, this is still the case - my mum hears far more often from me and my 2 brothers who also boarded than she does the others!
And the 3 of us who boarded chose to go for a variety of reasons and attended schools in several different countries. One of my brothers had very severe dyslexia and was able to go to a school that offered far more support than any of the local state schools. I was very academic and again, was able to attend a setting that offered far more than anything that was on offer at our local state day school. The other brother really wanted to improve on his languages, and chose to do what was initially meant to be a year in a boarding school in another country, and loved it so much he stayed for his entire education.