Whenever you talk about syndication, you have to deal with confusion regarding the multiple meanings of the term RSS.
RSS refers to the format Really Simple Syndication, also known as RSS 2.0.
RSS refers to the format RDF Site Summary, also known as RSS 1.0.
RSS refers collectively to all syndication feeds, whether they're in RSS 1.0, RSS 2.0 or Atom format.
I floated a proposal to the RSS-DEV Working Group last night to rename RSS 1.0 as RSS-RDF (RSS for the Resource Description Framework).
I'm asking for trouble by suggesting the idea, but as syndication has grown, RSS 2.0 appears to be eating RSS 1.0's lunch. According to the feed stats published on the syndication directory Syndic8, 76.3 percent of its RSS feeds are RSS 2.0 and 11.3 percent are RSS 1.0.
Here's their past Syndic8 percentages, using pages archived by the Internet Archive:
Those dates aren't necessarily correct, since they depend on how often Syndic8 runs statistics reports. But the trend is pretty clear.
We can debate the reasons why, but my guess is that RSS 2.0's higher version number is as much a factor as anything else. I expect that RSS 2.0 will continue to grow relative to RSS 1.0 because of Microsoft's choice to normalize to RSS 2.0 in Windows Vista and MSIE.
Each of the popular syndication formats has a strong selling point:
Giving RSS 1.0 the name RSS-RDF makes its status as an RDF format more prominent and allows some elbow room to open up between two similarly named formats with a common origin.
I'd prefer 'Deprecated RSS' as the new name for RSS 1.0 ;-)
I don't really have a strong opinion one way or the other. When I've had to make the distinction when writing, I'm pretty sure I've used RSS/RDF more than once.
If RSS 1.0 is only used effectively as an XML syntax for "simple syndication" then I can't see that it matters if people consider it an old version of 2.0. Its relative figures may be falling (and I bet you're right about the numbering being a big reason), but it's still useful as an RDF vocabulary for syndication-style content. In other words, it's part of a much bigger picture.
On the other hand, RSS 2.0 has built-in obsolesence. Aside from the issues the Advisory Board has had to consider, the spec is frozen with a very limited capability - crude content delivery. The extensibility offered by namespaced elements alone is fairly meaningless, anything you add is like a different language, requiring definition of how the stuff fits with the RSS terms. (c.f. iTunes RSS).
For my own stuff, I'm leaning towards Atom expressed as an RDF vocabulary (AtomOWL) as RSS 1.0 isn't so good for versioning entries. Doesn't really matter so much about the incoming format, if its a feed there's a good chance of it being crummy markup anyhow ;-)
"Whenever you talk about syndication, you have to deal with confusion regarding"... almost everything related to... "RSS".
Keep working to clean it up. Developers will appreciate the effort. Even if the Primer Mover's don't. I like the term Prime Mover more than Intelligent Designer.
As always, working on spec's (even when they can't be changed) is a major contribution to the Commons: thankless, frustrating, grinding attention to detail and clarity. It takes a special kind of person to move it along. You and the RSS Advisory members (and contributors) deserve some special rewards for these efforts.