More demanding games could help but at the most moment the market makes sure that any increase in GPU performance is eaten away through resolution increase.
Just because a smartphone or tablet has N native resolution it doesn't necessarily mean that all mobile games actually run in that resolution. Other than that desktop gaming hasn't stopped at 1560p either; watch how things evolve once more 4k displays appear and 8k waltzes into town after that.
Back to NV, an issue they face is that one of their main advantage, software, doesn't do much for them on those markets. Simply put most of task are not that demanding and the entry bar for good enough is easier and easier to reach.
You can have the best sw in the world, if your hw stinks, the first is not going to save the day and that works vice versa. NVIDIA has both excellent hw and drivers/support. The ULP SoC market due to having a high amount of large semiconductor manufacturers operating in, is practically ideal for IP sales. There it shouldn't surprise that ARM and IMG are as successful while selling intellectual property. On top of that NV, Intel and the likes jumped on the ULP train too late; it was probably a time when folks were giggling about smartphones and the mythical "potential" many saw in it, which in the meantime backslapped in their face.