The thing with this is, you are just quoting a belief statement. You are not addressing the text. These kind of statements are just random. Its not valid. The whole earth is mourning because they missed the return of Christ? SO the world was not mourning, no depression, no unhappiness before Bahaullah?
I think you should read up a bit about the evolution of the society of the world at large. It is not true that people are more depressed, mourning etc etc. Its just assumption that people make as usual, not based on study or any kind of research. This point is not based on anything, but a faith based polemical assumption.
The text says "all tribes of the world will mourn when the son of man comes", not after he comes, and not because they missed his advent. Thats absolutely false. Also, you still did not complete the verse. It says "They will see the son of man.....".
Dont tell me suddenly after addressing the tribes of the whole world, the writer changes it to "a few people". The whole world will see the son of man coming.
Please LOH. Lets not cherry pick from a cherry picked verse. I hope you understand.
Does it say instantly in one second? Or over a period of time? We believe that the whole world will come to believe in Baha’u’llah, every eye shall see Him.
When the victory arriveth, every man shall profess himself as believer and shall hasten to the shelter of God’s Faith. Happy are they who in the days of world-encompassing trials have stood fast in the Cause and refused to swerve from its truth. (Baha’u’llah)
Baha’u’llah explained what the tribes mourning meant in the Book of Certitude snd that to us is authoritative. My guesses aren’t.
“These words signify that in those days men will lament the loss of the Sun of the divine beauty, of the Moon of knowledge, and of the Stars of divine wisdom.”
The Kitáb-i-Íqán
Bahá’u’lláh