That is that it's just so unfair and unjust that the name they want was purchased by someone before them and that they can't use it or buy it cheaply or at all. [1] I don't know why people seem to think the Internet is different than other ways people make money buying and selling. For example coin collecting, art work, wine to name only a few things. And of course land and housing as you are mentioning.
[1] Try buying a domain name from google or a host of large "we don't need any more money" type of companies. You will learn to love anyone who is in the business of actually selling the domains that they own because given the right offer they will at least sell those names to you.
But the Internet landscape is very different and less finite in nature.
But adverse possession does not simply allow one entity to come in, declare the owning entity to not be using a property, and assume legal control. As a land-owning entity, I am not required to "use" my land, and as long as I kick squatters out in a reasonable amount of time, adverse possession does not affect me.