Considering I have knowledge in this area, I would say your fundamental understanding is off. No one is an island unto themselves and this holds especially true for the devout spiritual seekers. The hermit does, yes, spend a large amount of time alone. I've been a solitary individual a great portion of my life. However, they do so under the implicit understanding from everyone that it's sort of, their job. Part of the hermit's job, in being solitary, is also to return to the village so to speak, and bring back what he/she has acquired in their seeking.
The philosopher for example, emerges from isolation with his/her new philosophy. The monk emerges from his/her solitude with knowledge and wisdom concerning matters of the trouble of life, or suffering in general. The Buddha himself spent many years in isolation with those who sought an end to suffering. Their way of seeking an end to suffering was to heap sufferings upon themselves in the hops of becoming immune to them. Eventually the Buddha was by a stream one day and a young woman was passing by on a raft. Some one was playing a stringed instrument and he realized the philosophy of the, 'middle way'. If the string is too taught it will snap. If the string is too loose it won't play. After years of starving himself and living off of bird droppings and seeds and what not, he took the bowl of rice and enjoyed it. He left his fellow seekers who felt he had turned his back on them. He began to teach others what he had learned and eventually his old party came to follow him.
I think you are right, in that, there is something to be learned from loneliness, in that, there are lessons in suffering, some times, if not always. However, even the hermit is revered by the villagers because he/she has the bravery and the courage to do what they do not. And it is part of his/her process as a hermit to return to the village from time to time and bring back the treasures he/she has mined.
Being that I've enjoyed my solitude and had much of it most of my life (more so than most people could tolerate), and I've also been lonely, lately; I would say loneliness is not so much about being alone or being in solitude, it's more of a pain in the absence of some sort of, 'connection'. You can feel lonely even if you have lots of friends, or a wife, or a husband, or much family, etc.. You can also feel very much at peace and even better than you do when amongst people. Being alone can be a great respite from people. However, loneliness and being alone are not the same thing. Perhaps it could be said that the hermit who fails to return to the village from time to time, will too, become lonely. Loneliness implies a sadness, pain, and longing for connection. Being alone is something you can do for decades, while still maintaining connections, however small.
But, to feel cut-off, to feel a lack of connection with people, I think, is something altogether a different matter than that of hermitage and solitude. The hermit spends large amounts of time alone because he/she enjoys it and it is his/her nature to do so. The monk may do it, as it is often a requirement to be alone, to get to know one's self; and, there are also less attachments and hang-ups, therefore less distractions when seeking something. Just like it's hard to watch and enjoy a movie if you have a crying baby; so it is the monk clears out all those sort of distractions to do his/her work.
However, Buddhism does teach on this matter I'm sure, and there are things to be learned from loneliness, as there are lessons in suffering.
I would say, if you feel uncomfortable being alone, and are used to always being in the company of others, than suddenly being thrust into solitude will be difficult and you may feel lonely; but, this difficulty you have is also an opportunity to get to know yourself and grow. If you are used to being alone and now it is not so enjoyable as it once was, perhaps it is time to return to the village and see what's going on and offer what you can, if you can, if anyone finds useful any of the treasures you have acquired. And still yet, other times, perhaps like there are times of drought for the farmer, there are times of lack of connection for the person, and maybe this is when it's time to do a rain dance... and hope for rain, or have faith that the rain will come.