The commerce clause isn't "anything you want it to be", it's just a massively powerful constitutional clause. Perhaps one which the founders didn't anticipate being massively powerful, but one that was written that way none the less
When the founders wrote the constitution, the US was, for all intents and purposes a federation of states, largely speaking the states were independent and the federal government was essentially the arbiter of disagreements between them. That was fine and dandy back then because that's how things actually were, there were very few multinational or even interstate corporations in existence and to most people the neighboring state may as well have been make believe because they'd never see it.
The world has changed, interstate companies and even international companies are now the norm. Pretty much every commercial transaction you take part in is interstate, and so the commerce clause applies to pretty much everything you do.
It's sort of one of those problems facing most federations(including the EU for all that it was formed in the last few decades). The model works great when states are largely independent, but it falls down very quickly when they're not as you end up in this situation whereby either the arbitration powers of the federal government become all encompassing or the federal government can't do its job due to extensive restrictions. In reality it's probably time for a lot of countries to take a fresh look at their constitutions and make a judgement as to what should actually be the domain of the states and how exactly that's all going to work now that states aren't, for all intents and purposes, independent countries. How do you regulate Goldman Sachs? Which state or local government controls them? Do we regulate them where their corporate office is(City of New York)? Where the client lives? Where the transaction took place? Which level of government is closes to Goldman Sachs? To the Mississippi River? To Microsoft, or Google, or Apple, or your bank? Perhaps unfortunately there is very little that can still be effectively regulated by the states, let alone local government.
That's not to say the court isn't corrupt and partial(though I'd suggest that has more to do with the process of picking judges than anything else, Supreme Court appointments are not based on merit, but on politics, so unsurprisingly Supreme Court Justices are political creatures), but the explosion of the commerce clause isn't really a result of that.