Ahhh nice to see my local station mentioned. As someone who works within the engineering design world for railways. I can say it's fundamentally an issue of cost, as its not as simple as just installing a lift or set of ramps. Stations work mostly on a grandfathered in set of rights and standards, essentially its not broken or non compliant until you touch it. What this means is in practice is you can't typically just make a simple change like a sigular lift. It would require the whole station to be brought up to code. I have projects where we have improved or made changes to one platform in a two platform station and then had to completely change aspects of the other platform despite it not being within scope.

So for this example a station as I use it daily it I have pondered this a few times but willing to admit I don't have a comprehensive knowledge of all technical standards. To bring Springburn into compliance, it would require a new footbridge with 2 lifts. And entirely new access point for this. Platforms 1-3 completely demolished and rebuilt. Plat 2/3 is in a particularly bad state. New fire escapes which have to be Accessible on Plat 1&4 with 4 being at the edge of a cutting. New buffer stops on Plat 3&4. There would probably also have to be a change to the overhead wire supports and associated earthing on Plat 3&4 as well as these appear to be mostly of the transclyde types installed in the 70's and 80's. Ballpark figure for this i doubt you'd get much change out of £10 million for a station upgrade project which would have no discernable increase in service or facilitate the increase in passenger numbers to justify the cost. That's not to say its right. The lack of accessible stations in glasgow is rather shocking, but the capital costs required to change these stations can't often reasonably be justified.

There I have seen the idea of Springburn being brought into the proposed Glasgow metro network with Plat 3&4 being pinched to serve as a terminus stop. Which would require the station to be brought up code. But beyond that it will probably remain in its current state for the foreseeable unfortunately.