Only 20% of Americans polled are against abortion entirely, it's not the powerful topic it used to be. You're right that marijuana prohibition is not a strongly supported topic either, or at least one that is met with a growing indifference. Almost no one (outside of Sessions) seems to have held strong opinions on the matter.

But regardless I highly, highly doubt this one law being overturned could be equated to states having free reign to do whatever they like, regardless of federal law. There are tons of these individual issues that are finely regulated between state and federal power balances.

Not to mention the Supreme Court doesn't work like politics where you trade one issue for going easy on another.