I would just make one correction to your logic,

the real value of miles is how much you can resell them for, not how much you would pay for them... So for example, if you taking EK as a benchmark, you shouldn't focus on how much you would need to pay for a certain number of miles, but how much these miles will allow you to save if you book a flight with miles rather than cash...

Example: If a DXB to LHR cost 500USD with tax, and the same ticket can be booked for 10,000Miles + 100USD tax, then 10,000miles are worth 400USD.. That is 40USD per 1000miles...