Ta for that BM. There was a discussion particularly on indicators a little while back. And indeed, my '76 Jawa only has a brake switch on the R brake.
You do see some 50cc 2T moped scooters, and 2T off-road bikes. But I admit, 2t motorbikes on the road: they are mostly mine. So 2-strokes shouldn't become a major political issue.
On your last point, a long while back I learned that cars roughly cost as much energy to produce, as they will use during their life time on the road. Let's not forget that the production of iron ranks with the highest ecological footprints.
But of course, if someone buys a new car after just 3 years, that does not mean his 'old' car is wasted; it'll be used elsewhere. But indeed, what it does mean is that using your car (or motorbike!) as long as possible, is a very Greta-friendly thing to do, and should be encouraged.
Most cars (and other items) are often discarded because the repair/maintenance costs outweigh their commercial value (alternatively because they want something bigger & more luxurious, but that is probably less common). In the west, manpower costs are generally the main component of repair costs (remember that manpower costs are also included in the production of replacement parts). We keep our bikes running indefinitely because we do the work ourselves, and apparently we don't mind doing the work for free.
Anyway, high wages are unecological because they encourage early replacement, and thereby enhance the need for resources and increase pollution.
On the retro-active bit: that may vary from country to country (though I recently learned that apparently EU legislation takes precedence of local legislation...), and here, like with stocks, experiences from the past may not determine what happens in the future. Rules may change. Think of smoking in various places, over the years.
In various metropoles in the world, local governments have started low emission zones. Explicit rules vary, but the general idea is to ban polluting vehicles from densely populated areas. Since a couple of years now, vehicles get, in Europe, an environmental classification, Euro 5 is the latest for motorbikes. This EU* rating is part of the vehicle registration, and vehicles not complying with the latest criteria will not be approved for road use (which is why there are no new 2T motorbikes, or cars) in the EU. And then smart cameras check your environmental level from your number plate when you enter such a zone. To my knowledge it is not really banned anywhere, yet, but what does happen is that your wallet is drained. Particularly if you own a classic vehicle in such a big city, you're fcked. Recently there was a big protest of classic car owners, because in some cities they saw their annual fixed costs increase by 1000%, while they normally drive less than a 1000 miles per year (and not in the city!). Anyway, if you're interested:
https://www.lez-belgium.be/en/ (yes my taxes paid for making this)
An earlier thread relevant for this topic is
viewtopic.php?f=19&t=11627