I personally think that abortion is wrong in most circumstances, so yes it makes no moral sense to have abortion on demand in Vermont and Mass, but to have it available only in rare instances in Mississippi and South Dakota.
But having that mixed, checker-board system where the people get to decide is better than having the policy imposed from an imperious Sup Court.
If in overturing Roe, the Sup Court found that the Constitution, including the 14th Amendment, is silent on the issue, then the only way to federalize it would probably be through an Amendment. Neither side could muster the support to pass a firmly pro-life or firmly pro-abortion (or choice if one prefers) Amendment. So it would probably remain with the states, though obviously a Congressional ban on partial birth abortions would easily pass as it has many times already.
If anything, the 14th Amendment (as you mention) could have been the basis for denyiing the state's right to decriminalize abortion; but it couldn't have been the basis for affirming decriminalization (and indeed it wasn't). And of course there was no explicit power of the Supreme Court to act on a right reserved to the States in the first place!