A lot of AAA games are becoming so expensive to develop that publishers have been pushed to use DLC with parts of what used to be part of the game historically. So far DLC has managed to work when the costs are reasonable but some have abused the DLC model which has attracted a lot of criticism.
Bethesda and Electric Arts are two of the largest game companies who spend a mint developing AAA class games. Ubisoft is also a larger developer with a smaller portfolio of games and they are reliant on Steam for marketing games.
One of the biggest problems is the high cost of workers. For that reason many game developers have established offices around th world. Training schools for 3D Studio and AutoCAD struggle due to high overhead versus a small student pool.
Loot boxes have also been criticized as pay to win etc. or are nothing but gambling. So far only a few games have been using them but they are starting to be used more widely.
Recently the game Overwatch has used loot boxes as a marketing tool by offering 5 for free for playing the game. Overwatch was released in 2016 so the publisher has used loot boxes as way to get players back and to get others to buy the game.
The rise of free to play can be seen as a playable demo of the game. The bulk of the game may be offered at full price as DLC or it may be al la carte with pieces. The growth in free to play has changed the marketing model considerably.
Lots of development packages are now available and some independent developers are finding some success.