The wild strawberries I assume are F. virginiana - I collected them from a local field, where they do fruit but very sparsely. They've spread very well, they're healthy, they have lots of flowers but like the musk strawberries, the fruits never develop. They're growing under a row of pines with open exposure to the south, so they should have enough sun.

Wild strawberries don't need a male do they? Or have I just taken a poorly yielding strain? Any recommendations on a good strain?

What drives me crazy is that the yellow-flowered Indian strawberries (Pontentilla indica, non-edible) flourish and bear like mad. Happy birds, unhappy gardener.

If you have wild collected Fragaria virginiana, you could indeed have a strain that has separate male and female plants. There is a huge amount of variation in this species group across its range. Even some clones that have perfect (i.e., with both fertile male and female parts) flowers are self-incompatible, meaning there would need to be at least one other clone present to successfully bear fruit.