Once again, I will state the obvious. If you enter into a contract with a 13 year old to purchase a car, it does not matter how perfect the contract is, it is null and void and not legal. When you make standards IMPOSSIBLE and you KNOW it is, it is also considered null and void and predatory. The emissions standards for diesel were lowered way too fast and by too much. They knew this and did it anyways.
Yup.That's what happens when you have politicians setting the standards instead of engineers.
I don't think it's as simple as that. Europe pursued similar tech (DPF at least) earlier than the US. US focus on NOx is more intesive than Europe's due to CA smog/ozone issues mainly, but Cummins and others (Detroit, Volvo, Mack, PACCAR, Ford, GM, etc) proved it was all achievable. And industry/"engineers" were in fact very much at the table and providing input during development of the regs. The standards were ambitious for sure, but they were intended to drive the introduction of new technology, so they had to be ambitious. It wasn't meant to be easy, but it was far from "impossible" and the success of those manufacturers that hit the targets proves that case. If the "engineers" were in charge of setting all the emissions standards we'd probably still be using Quadrajet carbs and leaded fuel and mechanical P7100 injection pumps on our diesels, LOL.
Were there some who failed to make it to market successfully, or concluded the cost benefit didn't pencil and decided not to try? Sure. There were those who got into trouble due to poorly thought out technical strategy (CAT, Navistar being examples) and then after a few terrible years and/or violations, decided to leave the on-road market. Then there was VW, FCA, and others whose AECDs were either defeat devices or right on the arguable line, leading to cheating violations. And apparently Hino now in that category as well. But for every mfg that failed or gave up, there were others that succeeded.
Was/is there some pain for consumers dealing with new technology as it worked its way towards maturity? Sure. Expensive DPFs, SCR system issues, oil dilution, etc. But worth it in the end and the technology now 15 years later generally works well, even as complex as it is.
I think it's mostly just a matter of economy of scale with medium duty manufacturers choosing to give up and spec a Cummins powertrain. Cummins' whole game in the market is to be the leader in US emissions compliance. They have worked hard on that and done such a good job getting their products there that it just makes more sense for vehicle OEMs to buy their engines than try to market their own, in a medium duty world where the sales numbers just aren't that high. Why would Hino go through the trouble of certification, then, stocking spare parts, technician training, etc, when Cummins has a strong alternative? Buyers also like the fact that they can take their Hino truck to a Freightliner/etc dealer to work on the Cummins engine or get parts... that's a selling point for many folks, especially since Hino's sales network is mostly clustered on the west coast. This expands their appeal and reach.
15-20 years ago there were a lot of engines out there in the medium duty world. Cat, Navistar, Cummins, Hino, Isuzu, Nissan UD, Mitsubishi, and more. Nowadays, almost no matter what truck you buy in this size class, it'll have a Cummins. A Class 5-6 International, Mack, Kenworth, Peterbilt, Hino, Freightliner..... a B6.7 Cummins is the only choice you'll find available in EVERY SINGLE ONE. The only alternatives are the GM and Ford medium duty chassis which use detuned versions of their PSD/Dmax V8 pickup truck motors (cost effective because they are certifying those anyway so no need to go to Cummins), and I think Isuzu and Mitz still have their own engines in their chassis as well (?).
Kind of a shame in the case of Hino because the J08E was a sweet engine, better NVH than the Cummins has, and it was good to see something different available. Anytime a market gets so consolidated like this it's a loss to the consumer in terms of choice. But I understand their decision on a $ economic basis.