This is more or less how Ghostscript used to be licensed, if my memory is correct. New development was all released as “Aladdin Ghostscript” using some kind of no-commercial-use license, and then re-released under GPL later. Wikipedia says they stopped doing this sometime around 2006
This is an interesting idea, though I’m not sure how I feel about it. Another variation is the “GPL promise” that dmfs has for CalDAV-Sync and CardDAV-Sync for Android. (See their wiki for status and details.) They want to make some money to continue to fund development until it’s considered complete, so it is closed source and costs a bit in the Play Store but will open source it later on. Having a time limit until the state of the software has to be reviewed would make it a bit easier to accept like this author has.
Steve Coast (of OpenStreetMap) suggested a similar concept he called “License Ascent” last year:
I propose we engage in some kind of license ascent over time. Perhaps descent would be better. Under this scheme, some work starts out under a restrictive and painful license and over time makes it’s way in to the public domain. … We are reintroducing the concept of the work leaking in to the public domain gradually. So when I first create some piece of work I own it outright and then over time it becomes less and less burdened.
“Timebomb” implies that something bad happens after a while.
I don’t think this is a good term to use. Call it delayed-GPL or something.
fwiw, I don’t agree with licensing software this way. I just thought it was an interesting idea.