Does Japan accept permanent non-Asian immigrants?

Yes, if you meet their requirements.

http://www.moj.go.jp/content/001241940.pdf

http://www.immi-moj.go.jp/newimmiact_3/en/

Yes, and there are new immigration programs in Japan. The problem for Japan is the best educated/richest immigrants invariably want to immigrate to traditional nations to immigrate to, the US, Canada, Australia.... Therefore well qualified applicants who try their luck in Japan are likely to do OK both from the POV of their application, and their search for work. JLPT is the ticket here. 

Yes. If you meet the legal requirements, it does not matter where you are from.

In this covid situation, they may not accept readily. Anyway, you can try. You need to have the skills to adapt to their workforce requirements.

OIder Japanese people are not welcoming of strangers.

Depends on your job skills . Not an easy task , but it is possible .

Japan's birth rate is way too low , and she will have a shortage of workers

in the future .

Japan has traditionally not been welcoming to immigrants of any kind. However, like most developed countries, they have a very low birth rate, and they have found that they have to accept immigrants as a way of maintaining the work force. That doesn't mean you'll ever blend in or be able to become a citizen. But I know quite a few Americans who have lived in Japan for 20-30-40 years, married Japanese citizens, and done very well there. 

Yeah. Japan is accepting Asian immigrants since years ago and accepting it more recently because of labor shortage caused by population decline. Although it might be less just now because of pandemic. If you are in Japan with a long term visa, you will have chances to get permanent visa later.