Cap and Trade embeds itself and becomes a part of permanent energy infrastructure and can suck in as much money as they want to make, while completely distorting and controlling energy and manufacturing capacity markets.
EPA regulations are temporary, not permanent, can be easily undone by another administration and, while controlling and distorting the markets, don't bring substantial and direct financial benefits to financial community and even majority of politicos. Just a sop to "greens" at the expense of economy, employment and tax revenues. Much pain, little gain.
Cap and Trade is the ultimate prize, but in the meantime, they try to make some scratch with mandating "clean energy" in the form of wind and solar, because they are so invested in them.