compare the last release dates

    2012 Allegro CL  9.0
    2015 Allegro CL 10.0
    2017 Allegro CL 10.1
    2024 Allegro CL 11.0

    2012  LispWorks 6.1
     2012  LispWorks 6.1.1
    2015  LispWorks 7.0
    2017  LispWorks 7.1
     2018  LispWorks 7.1.1
     2019  LispWorks 7.1.2
    2021  Lispworks 8.0
     2022  LispWorks 8.0.1
 

Looks similar to me. LispWorks also had patch releases in between. Both are on the market for more than 35 years. Both are mostly written with CLOS and thus are especially to update with patches, additionally to the usual ways to update code (-> late binding). One just loads patches (which are mostly compiled Lisp code) into a running Lisp and that's it. Alternatively one can save a new image with patches loaded.

When one needs a patch or a feature, one would typically contact them directly. Both provide patches to the users.

Franz has made that simple for the user, they have a relatively continuously stream of patches, one can call an update function and it gets the necessary patches and installs them.

SBCL has monthly (!) releases, where the user (that's what I do) would typically compile it from scratch using the supplied sources. Updating is quick, around a minute for a recompile.