That is the theory. The reality is that at these scales a great many laws target only a single company. To target the leader in a given industry all a legislature need do is put a lower cap on enforcement: only companies beyond X number of employees need comply. At the other end, local governments certainly provide special legal treatment to individual companies (zoning/tax incentives etc). So while I agree it isn't a good idea, I'm not naive enough to say that every law targeting a specific company is delusional.