There are two basic approaches to engineering/economics of this kind of equipment. There's the commercial type of equipment that's made with long-term longevity in mind, aimed at professionals who won't balk at a $12,000 mower because it's a principal tool in making their living and reliability/uptime matters a lot. Equipment designed for these customers is generally built for the long run with good serviceability and support because there would be no market for it otherwise. The engineers and marketers know that it's worth putting that extra margin of strength and durability in it because they know it will pay off in the long run with a good reputation and a loyal customer base.
Then there are the penny-pinching homeowners who whine about every dollar something costs. Those generally aren't the people reading and posting in this thread, but they are BY FAR the largest population in this market segment. For this market, the engineering/economics dictates that the equipment be cost-engineered to hit the market price point(s) and to make it through the warranty period. There's little thought given to longevity and serviceability because 1) the customer base has no loyalty other than price, 2) homeowners don't take care of their equipment, so why add extra cost by making it serviceable, 3) anything put into the equipment that makes it last longer than the warranty period is foregone profit.
Case in point: how many homeowners buy Scag equipment? Not many, I suspect. Take their ZTR line for example. In the low-to-midrange equipment, what hydros do they use? The ZT-3100. They could (actually, they did briefly on their low-end ZTR, but only for a year or two) use the ZT-2800, which is identical except for the gear construction. The 3100 has real steel gears, the 2800 has powder gears. But since they understand their market and they're not morons, they choose the more costly parts because they know that their market demands that and in the long run, it will pay off with reputation and customer loyalty.
Unfortunately, we're caught in the middle. Not to say that we're cost-oblivious, but I believe that most of us here understand what we're buying and would be willing to pay an extra hundred or three for a more robust hydro and thicker steel in the frame than we find in what's offered to us. My recent tractor shopping was a little exasperating since I was constrained by the size of deck (storage limitations), and my aversion to flimsy stamped-steel decks - too many tree roots to hit. Plus, due to some slippery and irregular ground conditions, I was determined to find some kind of limited-slip or locking differential. A ZTR was not an option because of towing my Cyclone Rake over the inclines that are everywhere around the house. That narrowed the selection to basically one choice, and it has a K46. I'd have been a whole lot happier paying a couple of hundred more for something sporting a K66 (as long as it had the locking diff), but that's not an option in smaller machines.
So I'm resigned to making the best of a compromise situation. That means as a minimum yanking out the transaxle every 100-200 hours for an oil change with premium oil. It may mean adding in a real filter at some point after warranty expiration. It's not an ideal situation, for sure.
BTW, TT does not actually have their head in the sand. Read what they say about maintenance here:
https://www.tufftorqservices.com/EnvEEdefault/FlatHTML/TechInfo/ttcoil/pdfs/OIL CHANGE FREQUENCY.pdf
