because if an asic company went through all the time and expense to develop and asic and then use it to mine it would be very short sighted. Most companies are in it for the long game. They could spend the large chunks of money for development and deploy their on product and then spend a long time breaking even or they could sell them and make a profit immediately while at the same time increasing their customer base which leads to larger investments and profits over and over again. Using their equipment just to mine ould be tantamount to getting a golden goose and then killing it to see here the eggs come from instead of just letting the goose do its thing
+1
And unfortunately if they do suceed to the expese of the rest of the community (as was said above) bitcoin dies. But perhaps if they are doomed by their own success once they bail due to a lack of interest the individuals may be able to jump back in.
However if they want to suceed they should be bringing in new business and community members with thier hoards of cash not just using it to dominate the current market.