Where Im stuck as is that why power factor is set near unity like 0.8 or 0.9 but never unity.

The Power Factor (to be precise, displacement power factor) isn't set to 0.8, 0.9.

A generator will be capable of producing VA. If a resistor was place across the terminals then the the DPF & PF would be 1. It is the load that draws reactive current and the phase shift is dependent on the load. This can be compensated by some reactive components so the supply see's a DPF closer to unity, but this doesn't change the fact that the load will draw a non-unity DPF

Where Im stuck as is that why power factor is set near unity like 0.8 or 0.9 but never unity.

The Power Factor (to be precise, displacement power factor) isn't set to 0.8, 0.9.

A generator will be capable of producing VA. If a resistor was place across the terminals then the DPF & PF would be 1. It is the load that draws reactive current and the phase shift is dependent on the load. This can be compensated by some reactive components so the supply see's a DPF closer to unity, but this doesn't change the fact that the load will draw a non-unity DPF