Blink dogs clearly summon (the message indicates that) other blink dogs, while worms, jellies and bugs multiply.
I have always considered summons to be independent beings once summoned: there are situations when the summoner steps on an alarm trap and promptly gets attacked by his own summons.
I remember necromancers getting paralyzed by their own ghuls and spiders poisoning elven priests/princelings to death.
Great red wyrms obliterating their summoners, lich kings, and other summons.
They drop items, corpses, give exp. They interact with the world, activate traps, open doors.
With that in mind I see absolutely no justification for them dying when their summoner does.
To answer your doubts gr3ybird: yes, I want this game to be better.
I just disagree on how to do this best. In this particular case I don't think proposed changes do the job.
I mentioned summoners being annoying but that is true for many other elements of the game, yet I take it all in stride and don't complain.
On the other hand, summoners used to be extremely annoying by summoning endless hordes of monsters, sometimes 5-6 turns in a row.
That was excessive and when this feature was toned down, I felt the change was fair and I had no more complaints.
I seem to recall a lot of people sharing my thoughts on this.
Improving the game in my opinion has less to do with changing existing mechanics and more with adding greater randomity.
So, more quests (mutually exclusive as well), more items (notably artifacts), perhaps more skills.
I'd like to see more logical changes in the game, some of which might make adom easier, but respective RFEs are usually downvoted to oblivion or "balance" is quoted as the priority.