More or less, I think that's a decent summary!
Basically, if you were to remove all of the dead subs from everyone's series, then the people with more active subs that receive more likes, comments, and new subs will still be beating out the series that receive less. Instead of their being a ratio of dead subs to active ones, there will instead just be flat numbers of "hey this series that receives 2,000 likes per episode will be ranked higher than the one that gets 200 likes per episode, which beats the one that receives 20, which beats the one that receives 2".
The only people this would stand to benefit would be those with an abnormally high ratio of dead subs which isn't typical unless the creator is unnaturally inflating this number through things like sub-for-sub. And even then that would still just move them slightly above other people in their same "weight bracket", so to speak.
This is basically why I don't think Tapas (or any other site with similar algorithms) would necessarily feel the need or want to go out of their way to develop systems to nullify the impact of dead subs... in the big picture there's just not much need.
Lastly, I do understand and sympathize with the sentiment about wanting to tackle the dead sub "problem": as we all know, just having good content isn't always enough to build a readership. There's also an element of "right place at the right time" involved, and since dead subs impact our ability to reach at least trending (and maybe popular to a lesser degree) it's sensible to point fingers at them.
However I'm a strong believer that if you're a prolific creator that pushes out quality content then your audience will find you eventually (granted they exist on this site) and you won't need to worry about things like dead subs anymore anyways. Being prolific is important to get your work in the public eye as much as possible (as well as the one list a creator can control themselves appearing on is Fresh, so again- lean less on the algorithm and more on what you have control over), and quality is important because... even if you do appear on trending or popular, if people click your comic and decide not to read it anyways then it doesn't matter. In short, it's about creating your own luck~
(sorry this got long again despite being a response to a summary )