It's not that you cant recycle emissions equipment, it's that mechanically totalling and landfillimg cars once they hit 10 years old and are no longer supported by the OEM is stupid and environmentally detrimental.
Take appliances for example, the government basically mandates that they're energy efficient but the new linear compressors break. Cars got more efficient by tightening tolerances. There's always going to be an engineering tradeoff between reliability and efficiency. I just think the environmentalist types have been laser focused on creating efficient by non durable products that fill landfills.
And what percent of diesel emissions are from diesel passenger vehicles?
Emissions reduction efforts would be better spent ensuring repairability. The sunk cost emissions of landfills filled with junk created by planned obsolescence is much worse.
Diesel pick ups are not practical vehicles. Let's be honest, it's a hobby. It's always going to be niche and cutting down the last 10% is always the hardest. General aviation still uses lead.