They've already answered in the past by the same answer sqiddster already gave.
Also IMO, it's unlikely they will "give it for free" to past owners.
When you buy a cinema ticket to one movie, it doesn't automatically gives you a free ticket or a discount for the sequel, does it ?
Just be aware that all updates for Construct2 are free and this alone makes the price of the license worth (there's already been more than 80 updates since the first public release). If/when Construct 3 becomes available, I'd consider it natural getting a new license.