And why would you guess that? Because I don't consider LINQ of Rx observers being a magic cure-all? In fact, LINQ on Rx is a symptom of the classic LINQ issue

And why would you guess that? Because I don't consider LINQ of Rx observers being a magic cure-all? In fact, LINQ on Rx is a symptom of the classic LINQ issue -- don't have subscriber or source filtering, or coherent, useful events -- simply broadcast everything and through the magic, free filtering of LINQ all is solved in the consumer.