Indeed. And when I had a situation similar to this one a couple of years ago, the agent I spoke with said she could change the unchangeable flight for me but that once she did this, there would be no more changes, and that was suitable to me. However, considering that they have tightened the rules and increased the minimum number of flights purchased and raised the cost per flight, I guess they are selling more than enough and don't really need to do any more than the bare minimum.
My issue with Aegean on these sorts of things is that they really are a confusing company. They can be extremely consumer friendly in certain aspects, particularly to loyal customers, while on the other hand, on some issues, they can even go so far the other way as to break the law, as they did by refusing refunds for cancelled flights during the pandemic and by refusing re-routings when flights are cancelled. Overall I am still satisfied, and happy to continue going out of my way to fly with them when it suits me, though I also feel that the way they love to change the rules without notice and at the last minute is incredibly frustrating and could easily result in a situation where I would no longer bother to continue the relationship.