Is there a time after which software becomes automatically free?

[kedawa]

Illegal is not the same as wrong.

If games automatically became free after a limited amount of time, then alot of people would just wait.

You actually think people would wait decades to play games just to save money?

[kedawa]

Illegal is not the same as wrong.

You actually think people would wait decades to play games just to save money?

[kedawa]

The only crime would be selling that abandonware for profit.  If someone's willing to pay for it, then the money should go to the creator or rights holder.

[kedawa]

For the purposes outlined in the OP, you don't need to wait any amount of time to reverse engineer the software and release your own mods, so long as you don't distribute the original software with it.