that's not even remotely the issue. Money may buy you access but it doesn't magically buy you votes. People could easily kick every oil lobbyist out.
The genuine reason is that citizens are not willing to internalize the costs of their pollution and change their habits. Cheap gas, big cars, big houses, cheap Big Macs, cheap plane tickets is what the people vote for. Big Oil just supplies the juice.
The voters in the 70s and 80s did, sure. But as this article explains, those voters were withheld crucial information that could have informed their voting choices.
2010 was the first election I was eligible to vote in, and in the past decade+ I (and many others) have not voted for pro-oil/coal/fracking/etc candidates. Yet we're the ones that are (and will continue to) live with the consequences of Big Oil's actions from decades ago.
they are still voting for them, for example the House of Representatives is now majority Republican who almost all don't believe in global warming or believe in it and believe "eh, whatever, I got mine". Are they not as guilty as Exxon? Are the people voting for them any less responsible than Exxon. If you participate in the modern economy, are you not also complicit?