Originally Posted by Kordanor
At the same time however we move further away of reusing the same engine.
If you think back to Eye of the Beholder 1,2 and 3 for example , or Ishar 1,2 and 3. In the past you re-used the whole engine, just made some tiny adjustments and put in tons of new content and released the game again for the full price.
This almost does not exist anymore today. Instead we have DLCs.