Agreed. Good developers are good developers. The same traits that make someone successful on one platform are identical to what will make them successful on another.
If you pay more for certain training backgrounds, you're paying only for the few weeks/months required for a good dev to come up to speed on the new technology. The company in the article probably spent tens or hundreds of thousands of dollars more than they needed to for virtually no gain, unless those few weeks/months made a critical time-to-market difference.
I recall at one of my companies we had some incredibly strong devs, but all with Unix backgrounds. We needed them up to speed on Windows and COM. We did two courses for them -- probably WinTellect or something (one Windows, the other COM). In less than a month we had a small team of Windows devs that were as strong as any I'd seen.
We hired for really bright people first. Moving them to the technology was pretty easy. And if one month is the difference between making and breaking a market, you may want to reassess the market.