Our decision to remove port forwarding was not a question of margins - it was a moral and practical decision.
Port forwarding is a feature with many legitimate use cases. This year it became clear that we had become popular for use cases we didn't want to support. Undesirable content and malicious services is a good summary. I'm not privy to more details than that as my main focus is research.
Technology is often a double-edged sword, but thankfully it is often also a net benefit to its users and society in general. Privacy online is exactly that kind of technology. Enabling anyone to host any service anonymously on the open Internet is another matter.
I hope AirVPN and AzireVPN somehow succeed with providing that feature while steering clear of its downsides. That would be awesome.
Nitpick: Mullvad is older than both Air and Azire. :)