Tonight i watched the Don Box, Steve Maine Mix 07 video. What i see is Microsoft trying to catch up. Now i personally feel that their WCF offering and C# 2.0, ASP.Net and so are miles ahead of other languages.
The issue is that they have been very pro-enterprise and less involved in the day to day hackers that are heavily involved in building many of the high profile web apps we see today.
However, i think a lot of the REST apps, driven by API's that use GET are medium term services..... on the way to what SOAP offers. I don't think SOAP itself is the problem, i think it's just that the people who would require the advantages that SOAP offers build more complex applications - they are the established companies, corporates and so on. People writing REST services won't want to manage session state, message level security and more - things that aren't easily avoided long term.
Many of the web api's out there using REST don't do a while lot in terms of message security, authentication, transactions or sessions. However, this is the initial wave - many of us ARE thinking of ideas requiring these services. There is also the evolution of web service interop to consider - a couple of years back i wrote some services that talk to Jave SOAP services and it wasn't easy. We did this internally on some basic ideas so could avoid some of the complexity of message level security and transactions and so on - but there was definitely thinking around scaling those services up - something only SOAP and not REST protocols would be fit for.
However most using REST are (like us) startups - larger scale enterprises are still figuring out what web services are and how they may be of value. They certainly aren't going to expose online transactional systems on the web via simple REST API's. Some may try, but most won't. So REST is a good start and no doubt will fit many scenario's but i firmly believe that as services get more complex SOAP will start to become a more popular format... i just cant imagine all my data being exchanged as hacked versions of RSS/ATOM :)
But I spent 4 years writing Perl code in the early 90's and everything worked great - until the time to build, tooling, scalability of the compiled langauges offered so much it was just too hard to resist. Microsoft just need to make the time to build simple REST apps as quick as the other toolsets out there - they have the complex, scalable stuff covered.
Oh, i'd like to see an Xml-RPC intergave to WCF services if possible!