Portacle is a great project. My concern with it as a recommendation is that Lispbox was a great project too, until it wasn't...or rather that the enthusiasm of the maintainers of easy to use Common Lisp projects seems likely to be shorter lived than Common Lisp (though perhaps Github may make this less a potential problem). The fact that people get paid to improve and maintain the Racket ecosystem as part of their day jobs in academia is one of the reasons I recommend it for 'how should I start exploring Lisp' (versus learning Common Lisp).
> the enthusiasm of the maintainers of easy to use Common Lisp projects seems likely to be shorter lived than Common Lisp
Not surprising, given that Common Lisp itself is pretty much immortal compared to the typical lifetime of things in our industry :).
That said, I know what you mean. I started with Lispbox years ago, and it was already feeling its age back then. I agree with your observation. Sadly, the commercial CL scene seems pretty weak - the two big players (Franz and LispWorks) seem to mostly keep to themselves and focus on the commercial tools they offer.
One of the 'legacy' features of the Common Lisp community is that it is socially acceptable to charge $2000 per year per seat for software. Though it is not something that I personally have a problem with, my view that paying for software is ok is not all that mainstream these days (imagine paying for a web browser).
What I like about Common Lisp is that it is not in flux and so when I Google up a question, the information I get may be ten years old but it is highly likely to be correct. The price is that the format of the information may be more like a technical textbook than a blog or a StackOverflow answer.
https://common-lisp.net/project/lispbox/