Well, I happen to think more kids are choosing gaming over those options. Which is what contributes to the increase in gaming sales.
The actual data shows otherwise. Youths are rejecting major consoles as a primary source of entertainment across the board (unless you count using the consoles as a Netflix streamer).
The increase in console game sales is due to growth in international markets and the fact that unlike in the 90's people aren't dropping games as a "kid's thing" when they hit adulthood.
The Entertainment Software Association publishes a report every year on the state of gaming. Inbetween the 2011 and 2012 years they made a large change in their criteria: they went from evaluating the gaming industry from a traditional perspective (traditional consoles, PCs and handhelds) in 2011 to a more broader perspective (IE including mobile devices) in 2012.
The differences then between 2011 and 2012 reports clearly show the facts, and show that console gaming is on the decline with the younger generation:
In the 2011 report, only 18% of gamers were under the age of 18. When mobile devices got counted in the 2012 report the number jumped to 32%. In that stat alone it is clear that consoles no longer have the mindshare monopoly they had with children in the 90's. This 32% stayed stable through the 2013 report, so it was accurate. The numbers for the sexes didn't change too much either, so it wasn't females skewing the numbers.
To go further though:
In 2011, when only the traditional industry was counted, the average age of a gamer was
37 years old. In 2012 after the change the average age dropped to 30 years old. If console gaming still dominated youth mindshare that number should have RISEN, not dramatically dropped. That number stayed stable in 2013.
In 2011, the average age of the most frequent game purchaser (the best stat to measure hardcores) was 41 years old. In 2012, this number dropped to the age of 35. Again, if your statement was correct this age should have risen. But it didn't.
The data is clear- consoles matter less to under 18 youths than any time since the NES was launched.
The record sales for console games isn't because millennials are buying more than 90's kids did, it is because those 90's gamers never quit. In fact, those 90's gamers are still the core of the industry and not the millennials as you would expect.
In the 90's, all the 20 somethings at that time (who grew up during the arcade boom) looked down on gaming as a kids activity. For those young 90's gamers, the entire industry grew up with them and they are still the core that keeps it all running.
That fact is clear to see in the industry itself- it is why the top franchises are mature themes like COD and GTA instead of the cartoon-esc Mario and Sonic.
Here is the data so you can look yourself:
http://www.theesa.com/facts/pdfs/ESA_EF_2011.pdf
http://www.theesa.com/facts/pdfs/esa_ef_2012.pdf