Its not the 17th century anymore, we can make those things from non-animal components. Leather and lanolin are a wholly unneeded vanity and for the vain they can just do with alternatives.
Regarding leather: if one cares for it, it last decades. No plastic replacement I ever had lasted as long as leather that was occasionally cleaned and greased.
Except in reality, leather is more or less a fast fashion item that comes and goes. People buy them and toss them as their fashion tastes dictate, again, its not the 17th century. Its very rare to have a leather coat you wear daily for decades. Even in poorer countries is expensive to get and treated mostly like a vanity item. Alternative fabrics and materials work just as well and they both end up in a landfill after a few years anyway. Also the leather industry is abusive and exploitative towards workers and exposes some of the most vulnerable people to carcinogens and poisons needed to "work" leather. Is your vanity item worth all this suffering?
Go to a sheep farm, and watch the sheering. That PETA campaign was complete bs; most sheep actually await and enjoy being free from their fluff.
EDIT: too many replacements are plastic, which is adding to the accumulation of plastic garbage.
This?
You could also watch Dominion where the sheep section at 1 hour 11 minutes does not show happy sheep waiting to be sheered.
My mum knitted me a hat and scarf out of wool (mixed with synthetics because 100% sheep wool is not ideal), it's great.
My hiking boots are made mainly out of leather, synthetics are no alternative. My day to day ones are synthetic though.
Good quality leather products are expensive; your statement on them being "fast fashion" is only relevant if you're rich, or if it's shit fake leather.
Also, good quality synthetics as a replacement for animal products, the 'outdoor' stuff, is prohibitively expensive - moreso than an equivalent animal product.
Not everyone who wears a leather jacket it looking for fast fashion junk that will be thrown away in a few years. There are a lot of people who take a "buy it for life" approach to their clothing.