Hey SP.

Why don't you make all your miners 1-2% devfee and open to us all?? You could make much more that way. Lot's of smalltime miners cant pay your one time purchase fee since they never make it back. For big timers you could offer an unlock key to get rid of the devfee. (not very hard to check for abuse)

Until now you create a fast miner, then it either gets stolen and distributed or someone releases a faster public version and you scrap it.
A continuous actively developed fast version would just keep being used.

Look how much EWBF made on ZEC, still used up to today even while its not the fastest anymore or is developed and improved for at least a year.