Exhausts used to be a regular replacement, but with catalysts, the exhaust runs hotter, and heats up faster, so even on short runs not much condensation is left inside. Downside is that with a significantly reduced demand, aftermarket suppliers are disappearing, and OE will make no longer available sooner. Then choice becomes limited, and quality generally poorer. One of the reasons, quite a few years ago now, I had a stainless system made for the Panda.
Two exhaust stories. When working at a large Rover dealer, we of course sold Unipart exhausts, which came with a 2-yr warranty. Sold well, except into Swanage. A small seaside town, where the locals don't travel far, so fill their back boxes with condensation, rotting them out very quickly. So the garages in that area preferred to fit cheap silencers, and often. "The last thing we need is a long warranty."
When I was running a Fiat Argenta, an OE exhaust was only a few quid more than any aftermarket system, so I got OE. A front pipe, twin branch to a Y-piece, then a pipe back to the first box, over the axle to a rear box. Simple. After only a few weeks, it started to blow at the Y-joint. Poor welds. Local Fiat dealer were not allowed to splash some weld on, so under warranty, they replaced the front section. One of the rubber hangers broke by the time I got home. The front pipe was so misaligned it was trying to exit ahead of the rear wheel, so one hanger was taking a lot of strain, lasting about 20 miles. Took a bit of arguing about that one, I got to replace the hanger twice a day, at home and at work, for three days, until the next replacement arrived. They gave me a bagful of hangers. I got used to heaving against the wheel to get it into position. Next replacement fitted well, but again the welds at the Y-piece failed, after about 6 weeks. While grovelling underneath to identify where, I was met with a glaring hole in the sill, like older Fiats used to. Had enough, went looking for another car, came back with a Panda 750.