How do you propose we issue licenses otherwise? If you pay a one-off for C2, does that mean you get free upgrades for ever and ever? Right now I have zero plans to ever create a "Construct 3". We're going to be incrementally upgrading, and producing new exporters, for the forseeable long-term future.
You do own the software once it's licensed and the no-DRM thing is directly aimed at allowing you to do what you like with the software (e.g. install to thumb drive, no phoning home). Once the license expires there'll be a notification which you can dismiss.
Is it so bad?