it was released because they could release it surely.
just go back to the Old Champ Manager days - there was no way of releasing patches so the game had to be tested to death, where as now its easier to release the game and continue to develop it with use of the steam updates.
They were both released in states that became genuinely unplayable for a large number of systems. By your argument they should have been released in better states because they had to be because of fewer patches/chances to fix, which was clearly not the case since they had memory leaks.
The system they use now is far more refined than anything they had way back when. On the other hand, the game is also considerably more complex. Steam allows them to compile a build within days of testing and balancing. So you dont have to wait as long before releasing hotfixes.. They could saved up all the fixes till jan like they used, Steam allows them to roll them out almost continously if needed.