I tend to agree with your end state (eventually, gas stations will be few, inconvenient, and expensive), but I disagree with the mid term. It won't be "chains" that will be decommissioned, it will be individual sites. Like most things, it'll start at the margins. The location on the wrong corner of a street that was barely enough volume to keep going will close while the one across the street on the more favorable side will stay in business. You'll also see it hit a point where "run it until it needs money" becomes the retirement decision. When the tanks need to be replaced, if it's a lower volume station, they'll just close up.
Societally, at least in the US, I think the bigger risk is that owners will close/abandon them and the taxpayer will be on the hook for cleaning up the soil and groundwater. We'd be smart to get ahead of this and start collecting enough fees now to be able to afford to help offset remediation costs for sites that get abandoned by bankrupt owners in 10-30 years. A small amount now (or a slowly building surety bond) could probably be imposed in a reasonable way now, without crippling the stations, but to build a reserve for remediation decades in the future.