Seems perfectly reasonable to me. The iPad Pro which seems to be the device you're referring to only has 4GB of memory which is shared with the GPU.

The minimum requirements (from steam) recommend 4GB of main memory and an additional 2GB of dedicated VRAM. Clearly this is an issue.

As far as compute performance goes you may be right however as it only recommends an Intel Pentium G3240 or AMD FX-4100 as minimum.