To all with "Online access for this account has expired", they are looking into it, just sit tight and wait for an official response.
I would think that you can cancel any subscription from your Account Details page (click your account name upper right hand corner in Steam), but...
Yes, I've completely removed my old rF2 install before starting the Steam activation.
I have the same issue, and when I activated my key it said "rFactor 2 with lifetime subscription".
And I have the same issue too, followed instructions but can't get it working (and I did not install in the Launcher folder ;)).
Separate names with a comma.