Who uses minecarts for hauling?
By the time the track is carved the stone is already in the stock piles.
With the new way trees grow, I like to set up indoor tree farms. I can designate a zone for fruit picking or have trees cut down, a nearby stockpile for accepting the goods, and a cart that follows an automated track to dump the goods in the appropriate quantum stockpile, often several z-levels below ground, then reset itself. It MASSIVELY reduces the amount of time it takes a dwarf to perform the task, which in turn saves tremendously on labor.
I also use minecarts (just set to "guided" for a path of one tile) to dump goods into a concentrated quantum stockpile in the center of my workshops that use them. I.E. all stone consolidated onto a single tile just two tiles from all my stone workshops. I can then quantum stockpile their outputs onto a single tile right next to the stairwell or ramp.
The single biggest limiter of productivity is hauling time. Legendaries produce goods nigh-instantly, but typically haul items 30 steps or more to get them. Make that into taking two steps, and you have just increased your productivity by a factor of 10. Even with haulers, if you put everything as a mere few steps from a central stairwell or ramp, and you can have a clean fort with 1/10th or 1/30th of the haulers. Do you have haulers idling because there's nothing left to haul? I have haulers idling.
Same goes for having a cart track from your main industry stockpiles to a quantum dump right outside the trade depot. Dump your vendor trash directly onto the vendors!
Also, keep in mind that if you set minecarts to "guided", they are basically just wheelbarrows with 5 times the capacity. No tracks required but at the ends. Doing this for new stone quarries you won't be staying in for long is an easy way to organize stone and haul it fairly quickly.