The struggle of playing with friends who have the same game but on a different console has been a problem for many people since online multiplayer was created. Countless friends find that their friends who own an Xbox One, while they own a Playstation 4, aren't able to play games that they both own, just on different platforms.
The idea of cross-platform gaming is something that should have a stronger focus than the constant increase in server sizes and bringing in more players per game to face off with. There are games who have attempted the cross-platform online connection with many glitches and issues, such as Portal 2. If we could get the connection set up to where anybody on a PC, Mac, or Console of choice can join the same server and match up against each other. This would completely get rid of the need of owning multiple consoles or multiple copies of the same games.
However, would this fact of lack in necessity to multiple purchases hurt the game industry? There have been drops in sales in comparison to back with the ratings of the Playstation 2, which is still currently the best selling console of all time, and this has caused issues for the companies like Sony before. These led to the price increase that we now consider normal; $60 for a brand new AAA title.
I don't think it would hurt the industry to the point where cross-platform online gaming would really cause a big issue in sales. Many games that would have the server option to do this would be games that are largely popular and have record breaking sales as it is. While breaking a record with sales would be harder, due to people only buying one copy of the game for their preferred console or system of choice, it would be much more player friendly.
Saving money for the players would in turn give them money to spend on downloadable content and in-game upgrades. It is possible that cross-platform gaming could be the answer to balance out the outrage that comes from the addition of micro purchasing transactions. While many would still be mad about the micro transactions, there would be a viable argument to put up against the backlash.
Overall, I think it would be an improvement to the game industry and replay-ability of many games. There isn't enough negative comments to make on this subject to outweigh the positive ones. I am hoping that the developers in the game industry start to turn their focus in to providing the cross-platform online match up's as a possibility that they can soon add to their games.