I won't make any suggestions, because they would all involve someone allocating more resources. But I don't think anyone wants to wait 150 days.
No, you're right. And it's one thing that particularly worries me a lot as I still feel somewhat attached to and responsible (and ashamed) for how things are in the Plugins directory. The plugins approval review process is actually something we should talk about and come up with a solution. Because the current state is not sustainable.
To put things into a wider context, it should be clarified that officially, HQ developers are not obliged to provide plugins approval reviews. They were kindly asked to do so and many do, as much as their time allows them to help. But as everywhere else, there are other projects, duties and patches reviews with higher priority (the moodle peer-review queue is even longer than the plugins approval one).
As far as I know, it's been envisioned that the plugins directory would be kind of self-maintained by the dev community itself, and the plugins guardians program was a step towards that goal. It worked, albeit maybe not to the full expected extend. And as of today, out of all guardians, it's effectively only Dan Marsden who pushes the boulder tirelessly (?) forward.
My overall feeling is that the entry standard evaluation bar has been set too high, given the lack of human power to provide such reviews. For sure, the approval reviews help to keep the quality of published plugins on a high level and from that perspective, I believe that things improved significantly. I am just not sure if the price for such a quality is adequate. It is not trivial to provide good feedback on day to day basis and the risk of burnout is high.
I'll be happy to hear the community's suggestions on how things could flow more smoothly. We have a wide range of alternatives including extreme cases like zero approval reviews. I am serious. There are many software repositories out there with very liberal approach, where any package can be published by anybody. And apparently they work and grow, too. Or, we could change the rules in more creative ways - e.g. automatically publish all submitted plugins but then have some levels of how well the plugin is perceived and used in production. Based on users feedback, ratings, stats and/or code reviews etc.
I think it's time to re-think what we (as community developers and moodle users) really need and what the plugins directory can do to support such needs better.