Don's point that OpenACS could be a "big tent" project, where people work on the flavor (AOLserver/Tcl, Apache/tomcat/Java, etc.) of interest to them is surely one of the main reasons behind the success of open source development.
My fear however, is that the community is not large enough to put a critical mass behind each flavor supported. While it is true that the flavors without critical mass will simply wither and die, it is also true that this dilution of resources can threaten us as a whole.
Michael's point that companies tend to choose platforms based on ease of obtaining resources is a good one. I've lost work simply because the client, while impressed with AOLserver, had a "legacy" Kiva environment, used Perl, didn't know Tcl, and wanted a more mainstream solution. It's interesting that in trying to sell AOLserver/Tcl, I've hit the problem of trying to sell into what amounts to a legacy environment, even though the web is only 5 years old!
Fundamentally, I think putting AOLserver/Tcl into a greenfield environment is not a problem. However, trying to pitch it to people who already have some investment in web infrastructure, no matter how rotten it is, is a lost cause.
From a technical perspective, I'd like to stay with AOLserver/Tcl. However, the reality of the market suggests we might all be better off migrating to a platform and language that integrates more easily into the most dominant platforms around. This appears to be Apache/tomcat/Java or even Apache/mod_aolserver (disregarding the problems noted in this combination).
Up until now, I've not used the ACS code, and have been developing an in-house solution. The AOLserver/Tcl combination was not a problem in this instance. Now that I've started to develop for external clients and need some of the functionality in ACS, the issue of where to focus my efforts rears its head. In these external client situations, the only reason for wanting to use AOLserver is because ACS has been tied to it. But selling AOLserver into a legacy environment is tough. I'd have a much easier time if ACS were independent of AOLserver, or if AOLserver were much more widely known and accepted.
If we wish to continue with AOLserver as the base platform, then it appears like we need a fork so that it can evolve more freely in response to our needs...