[oogali]

It's not just that a system built in MS Access facing scale concerns needs a rewrite from an engineer's perspective.

It's that the business will also accept that it needs a rewrite. As opposed to the current status quo where they'll ask what's wrong with continuing to use $Slick_and_Fancy_Tool (then act surprised when it stops scaling with regards to whatever business, performance, or compliance barriers you've then reached).