I "beefed up structure" would be significantly heavier, so there is no guarantee that it would achieve lower landing speeds even with longer flaps.
And it's not so much a matter of "money talks" as "this is the target market". There is no point in building an airliner whose specific operating costs are higher than the opposition. Airlines operate on a financial knife-edge anyway, and there's no slack available to accommodate a less cost-effective aeroplane.
The design of any aeroplane is a series of trade-offs between weight and cost, reliability and cost, reliability and weight, maintainability and cost or weight, take-off performance and cruise fuel consumption, landing speeds and operating cost, landing speeds and cruise speed, landing speeds and reliability etc etc. All of these are studied in nauseating detail before the basic configuration is frozen, and revisited at every design verification stage.
If they don't do this then they end up with a product no one wants to buy, and everyone goes bust. The staff are thrown out on the streets to starve in the gutter, turning to drink and drugs before deciding to end it all by hijacking an airliner and flying it into a nuclear power station, causing massive radiation leaks and the end of all life on the planet.
Against that I'd suggest a few extra knots on the approach speed is probably an acceptable trade-off - n'est pas?
