Making deals with individual companies effectively lowers the tax rate for those companies involved (i.e., taxes owed - tax grant = less money owed to state). Other companies would be legitimate in taking the state to court arguing that it is applying taxes unequally. The deal could end up being thrown out.
Yes, Donald Trump is meddling in the economy too much. The deal he cut with Carrier to keep jobs in Indiana in exchange for tax incentives runs afoul of America's long tradition of free-market economics. It is also unpopular with many on the left who see this deal as a form of corporate welfare.
Stocks have never been better. People are trying to give Obama credit for this accomplishment. But the truth is that stocks soared after Trump won the election. Trump knows how to run businesses. People have faith in him to make wise decisions that will benefit the economy of the entire country.
He made a deal for jobs, which all politicians do, but the real problem is that he traded for only 1,000 jobs and at a huge cost to the rest of Americans. The problem is not that he is "meddling in the economy" the problem is the kind of deal he made.