Mobile games continue to be the fastest growing sector in the overall games industry, worth about $70B in 2018. That's now more than 50% of total games revenues. All according to the latest edition of the Global Games Market Report from Newzoo.
We often talk about the scale of mobile games over other platforms. You have to bear in mind that mobile games are generally considerably lower cost to buy than PC or Console games, which means that to achieve the revenues they do, the reach has to be considerably higher.
The bottom line is that mobile is where people play.