To the cannabis-curious, possibilities are bountiful in a nation increasingly supporting the legalization of marijuana.

In some U.S. cities, nearly every block seems to boast cannabis dispensaries fashioned with a telltale green cross symbol. Inside, many resemble the modern minimalism of an Apple Store, and customers can find strains with varying concentrations of THC, cannabidiol (CBD) and other cannabinoids, yielding the physiological gamut between calm and energetic.

Two dozen U.S. states and the District of Columbia have legalized marijuana at the recreational level to date, with Ohio becoming the 24th just in November. With the exception of West Virginia, that leaves Pennsylvania surrounded by states that have in recent years passed bills legalizing adult-use pot — and vulnerable to losing out on potential profits. Close to $3 billion in tax revenue was generated in 2022 across states with legal cannabis, says the nonprofit Tax Foundation, based in Washington, D.C.

Cannabis legislation has seen bipartisan support in Pennsylvania over the years, including from state Sen. Mike Regan, R-Cumberland/​York, and Sen. Dan Laughlin, R-Erie, both of whom have sponsored bills to update medical cannabis policy.

Mr. Regan, in a 2021 post on his website titled “Legalization of Adult-Use Marijuana is Inevitable,” noted that his support stems in part from his years in law enforcement, including as a U.S. Marshal “at the height of the drug war.”

“Our law enforcement agencies and justice system do not have the manpower or time to handle these minor marijuana offenses that clog our courts and produce little return,” Mr. Regan wrote, while also nodding to potential “border bleed” as Pennsylvanians head to neighboring states — and help contribute to their tax revenue.

Gov. Josh Shapiro in his February budget address underscored a desire not to miss out: He said he wanted a bill on his desk to legalize the substance, estimating an annual revenue of more than $250 million from expanding beyond medical use in the state.

Even if that bill were to hit his desk tomorrow, the period from legalization to implementation can take years. Ohio legalized recreational marijuana last year but still is trying to amend the law; Pennsylvania’s medicinal program passed in 2016, but patients didn’t walk into a dispensary until 2018.

With so many factors at play, what might the transition from that medical marijuana model to a recreational one look like in the commonwealth, and how near is that moment?