Have IrDA dongles really gone the way of the dodo?

News to me...

I would have guessed that if the devices met the IrDA standards then comparibility wouldn't be an issue. I know some of the low power devices used a shortened pulse width but kept the same timing cycle.

Unless you are speaking about the baud rate of the SIR, I don't know about compatibility issues.

Which is why for all my vintage handhelds I own/use vintage infrared devices.