No, your speakers did not cause it.
Something has happened in the preamp/processor section. You have no sound on any channel. Your speakers would not blow all power amps at once. If the speakers caused the problem then it would have caused an output device to blow which short circuits the power rails and sends it into protection.
The bigger issue is that I believe receivers, never a good idea, are now going down hill to maintain price in the face of increasing complexity and bloat.
They are built with consumer grade components. So statistically the odds go up of failure with increased complexity as well as down grading the power amps to maintain price points.
So we either put up with a high failure rate or the cost has to go up and we progress to making gear with industrial or preferable auto grade components.
That would raise prices a lot. But you can't have your proverbial cake and eat it too.
Lastly, I doubt the Denon statistically will have a lower chance of failure. Denon and Marantz were bought recently be a an outfit that has lots of brands. We will have to see if there is a downgrade to the line under new ownership. If things follow usual form there will be.
I personally think there is a place for a high quality AV pre pro that just is 5.1 or 7.1 with bass management and HDMI and analog switching plus SPDIF inputs. Then just volume and nothing else. No streaming, no disastrous auto Eq programs. It needs to be as hair shirt as you can get and we would be better off I think. Then use good external amps. I think that could improve sound quality enormously and also reliability.
This is my downstairs rig, and built largely around gear from a better time now fading in the rear view mirror. There is no receiver or pre/pro, just an HDMI switch. I can stream anything I want. It sounds superb and is very reliable.
Personally I'm highly trouble and failure adverse. Reliability should be the top priority of any design, but these days that is bottom of the list. Send the gear out the door and the sooner it gets to the recycling center to pollute the third world the more money we make. Its a disgrace and I assure you, you are not alone. You have lots of now increasing company.