I don't think it's breaking news that diesels are being legislated out of existence. This is partially down regulations that will make it more and more difficult for diesels cars to pass their mots as they get older and more and more difficult for new cars to meet the constantly updated regulations.
In the case of new cars the cost and engineering complexity of making those cars meet those regulations becomes near impossible (hence whyVW cheated). It also makes the cars more difficult and expensive to maintain.
I guess that's fair enough as the world moves towards EV's but we should remind ourselves that in the 90's it was a new generation of turbo diesels which showed us we could have of economy and performance.
In the 90's I worked in factory doing IT things. I often had to take equipment out to site or as junior member of staff be sent off on courier missions to drop off factory samples to other sites . The rule was you could ask any of the managers who had company cars for their car keys, which included a Citroen Xantia, Volvo v40 and various other nice for the 90's cars. If I was really unlucky and none of these was available I'd get lumbered with the old 1.7 non turbo mk3 Astra van.
I was walking across the yard one day and as I walked past one of the warehouse guys he said. "Pssst, have you drive the new van yet? "No I answered what is it? "It's a Citroen and it's VERY fast. everyone is fighting over the keys it in the warehouse". Okay, right I said not believing him and casting a picture of an old C15 van in my mind. A couple of days go by and I'm asked to take something to a factory 50 miles away. The something is in a big box so I need to take the van, which turned to be a Citroen Dispatch with the 110bhp turbo diesel engine.
Once under way I couldn't believe how fast it was. My car at the time was a 1980 1.6 ford Cortina and I think the most powerful car I'd driven was the 2.0 petrol Volvo. The mid range punch this van had was like nothing any of the other cars had to offer. This made over taking a breeze compared to having to ring the neck of something petrol powered to do the same yet it still managed to do over 45 mpg and had car like handling. Even in the motorway I could keep it in 5th and with a quick squeeze of the accelerator I was off. When I reluctantly returned it and got in my Cortina to go home it felt like a model T Ford.
Around the same time Peugeot released the 306 D-Turbo, which used the mid range torque of a modern turbo diesel but in their new Pininfarina sled hatchback. From there we got the VW PD engines of the late 1990's and 2000's that went up to 150bhp in production versions and infamously (and as anyone who owned one would tell you immediately) were quicker 40-70 that an Impreza WRX.
Owners also started to figure out that as the car has a turbo charger you can turn up the amount of boost and that turns up the power and torque for not much money. By spending some cash on bigger injectors and a bigger turbo some serious power can be made usually to the eventual cost of the drive by knackering the drive shaft or making the gearbox explode.
Back in the real world by the mid to late 2000's thanks to company car tax incentives oneconomy almost every family and fleet car became diesel powered. The diesel engine was still relatively simple even with high pressure systems like VW's PDI. However as c02 output of a diesel engine is relatively low the particulates are high and this is the bit that isn't particularly good for your health. Regulation then stepped in to reduce emissions, which lead to things like diesel particulate filters. water cooled EGR systems and ultimately ad-blue.
To compound this the customers demanded more performance and more economy, which lead to things high pressure pumps and compound turbo setup to reduce turbo lag and increase economy.
All of this turned what was the a relatively simple engine into something containing multiple extremely complex systems. Out side of commercial vehicle applications I don't think many manufacturers will be developing their diesel engines. This may come as a relief to some who have been hit with massive fines for misreporting emissions and mpg figures and also because they must have been reaching the limit of what can be done to make a diesel engine run cleanly.
So as we wave good bye to diesels and usher in the EV's doing forget it was diesels who taught us we when it came to performance and efficiency we could have our cake and eat it.