Patent valuation is a difficult subject because there are many different people using many different techniques to come up with a ‘value.’
In general, the only meaningful metric of patent value is revenue.
Either you are selling a patented product, or an infringer is selling an infringing product.
The value of the patent is determined by comparing the patented product against a competing product that does not infringe the patent. If we can tease apart the extra amount of sales that comes from the patented product, then we have the best indicator of the patent value.
If there are no sales of the product, the patent does not have realizable value – YET. Once sales are established and we have an apples-to-apples comparison to a non-infringing product, only then can be put a meaningful value on the patent.