Finally had a chance to do a clean install on a 32-bit machine, and got farther than ever before on that platform, which suggests the original cause of this bug report has been overcome by events. However, when attempting to login, I found precisely this:
https://support.steampowered.com/kb_article.php?ref=4090-RTKZ-4347 "The Steam Browser is Disabled" and to quote from further down on this page: "Linux 32-bit Linux distributions are also no longer supported. Please install a 64-bit Linux distribution to make use of the Steam browser." This sounds to me like it might be the end of the road for Steam on 32-bit. Clayton