That is actualy a rather bold statement and might be true for common patterns. Scaling, (and pricing) RWD is really challenging for me when it comes to unkonwn things like this:
Fresh identity, responsive front page. All nice and smooth,right?
But how about this? http://www.itv.com/tvguide/
well... I guess they just gave it up here. I`m not saying it is impossible to implement but I have no freakin idea how to estimate a deadline for something like this. And itv is a big company, with a decent budget.
An other example is the famous bostonglobe.com. Beautiful site, working nicely too, but it has freakin ~12K lines in the css!
So plenty of blind spots all over the place, especially for small teams and individuals like me, when it comes to estimating, scaling and pricing.
I'd be interested to learn more about their design and implementation workflow, that they mention RWD taking 'almost twice as long'. How much time are they wasting building static comps that illustrate a picture of what some people will see when they come to their website? This is speculation - I don't know how much live prototyping they do in their design process.
I'll have to mention Edit Room again, my web design tool that makes creating responsive, multi-screen web layouts as easy as dragging things around on-screen. If you start your design work in the browser, you save so much time that lets you go that extra 10% on a design. That gives you the time you need to make your designs work everywhere.
However I disagree that making a design responsive today is an investment for the future. Designs change much quicker than demographics, so if they don't have significant mobile traffic today it's unlikely they'll have it during the lifetime of the design.
I find responsive design a cheap copout, jack of all screen resolutions, master of none.
Just create a good desktop design, and make sure it plays on a modern smartphone with tap-to-zoom. Tablets will work automatically.
I dont'see "more diversity of screen sizes" coming affecting this at all. New screen sizes will just be bigger than an 2010 iPhone/Android phone. Those can play well with desktop-sized designs anyway.
And even if you have a 30" monitor you still don't need more than 1000-1200 pixels of webpage estate anyway. For one, people can't read or follow freakishly long lines of text easily.
Even so, it's a matter of rate of growth vs lifespan of design, in the context of what your mobile users are actually looking to do.
Even if mobile use is growing, if people are only using their mobiles to do one or two things (say, search documents and view balances) it doesn't necessarily make sense to build and maintained a responsive design that delivers the 'full' experience on mobile.
Cost/benefit may well indicate it's better to do a desktop design + purpose-built minimal mobile design. Over time, things change and naturally the next re-design should revisit the problem.
But who knows? By then, people may be looking for interfaces and feature support for all-new devices. Say, wearables like the Pebble or Google Glass.
In terms of growth in mobile traffic, I have no doubt you are right. However, considering the lifetime of the design - I would be surprised if this number changes significantly before we do another redesign!
their decision might not be popular, but it is definitely right for them. especially in the short- to mid-term.
As far as RWD taking twice as long to design and implement, perhaps this is just a question of experience. Once you've had some practice with RWD, although it does take some extra time, I don't think double the time is typical.
The argument that only a few of their customers are on mobile is the strongest reason presented not to use RWD, but the question I would be asking is, "Is this situation likely to remain that way? Will mobile users only ever be 2% of our traffic, or can we expect that this proportion will climb?"
Personally, I would expect that this proportion would in fact increase over time, but I don't have a crystal ball and can't say this for certain.