This sounds like someone is trying to argue one solution for the whole world.
I'm in the final stages of redesigning a system I inherited and I have to say using the SQL Server for holding the business logic was a saving grace that will meet the future needs of the project and is very flexible. Why thank goodness for SQL? The project started with an MS Access front-end that is still the primary interface. Since then two differnet web sites are using the data and another unit is pulling information out. I should point out that I'm in a very decentralized environment. We don't move from one data server to another. Instead we have anything and everything. Most of the enterprise runs either Oracle, MS SQL, or MySQL but many flavors exist beyond that.
The article was also a good example of an interesting trend. Objrect oriented programming, and even more interestingly design patterns, refactoring, power porgramming, and their ilk, bring up a lot of good ideas. T-SQL is spagetti language but it doesn't mean that we can't apply a lot of the new ideas to what we do. Even if a stored procedure is going to do only one job, take the extra time to avoid hard coding, ask what is really being asked of the stored procedure, apply some of the refactor concepts to the code. My current project has grown as I suspected it might and I'm finding it's very flexible. Even where I've been suprised the stored procedures have been ready to take on the changes (my one complaint is the inability to handle nested insert execute statements).
I'm hoping to expand the scope of one of my systems to the whole enterprise. If and when that time comes, or if another large-scale project comes along, I'll be back in .NET C# or Java and trying to apply all the best practices I can along with other programmers to create a long-lived project. Also, with SQL 2005 I'll start to look for opportunities to move business logic in to C# or Java. But not this current project. The SQL Server for the business layer has been excellent, it's been flexible, and it will scale to cover the range of possibilities.
One size fits all, feh.