Over what, 30 million gamers already bought an xbox one this generation so surely the compelling reason has to be there somewhere. Just keep digging buddy!
If you had a choice to develop for a console with 70million gamers and 30million gamers, where would you as a business logically focus the company's efforts. Keeping in mind that for each platform you release on, means more overhead and more support you have to give. If I were running a company I'd focus on the 70million gamer market, then once the game has done well there, target the the 30million gamer market. If it doesn't do well in the 70million gamer marker, then I'm unlikely to waste my time porting to the 30million gamer market.
Let's compare how franchises sell on each platform:
A popular multiplaform game like FIFA 18
PS4 : 6.9 million units sold in 5 weeks
Xbox One: 1.6 million units sold in 5 weeks
That's a 4.3:1 sales lead to PS4
Assassin Creed Origins, the PS4 is 2:1 sales lead over Xbox One
Well lets compare how well Xbox One exclusives do, compared to PS4 exclusives.
Xbox One Forza : 395,000 units in 5 weeks
PS4 Gran Tourismo Sport : 1.2 million units in 2 weeks
3:1 sales lead to PS4
The list goes on.
All data taken from end of October 2017
So as a game developer, if I had to only develop for 1 console to keep costs down, the clear winner here is PS4, hands down!!
The numbers don't lie.