FOR MARK ZUCKERBERG, the first three quarters of last year were rough. In July 2022 his social-media empire, Meta, announced its first ever year-on-year decline in quarterly revenues. Three months later it reported another. Investors sneered at his expensive pivot from a lucrative ads business to the untested realm of the metaverse, on which Mr Zuckerberg was splurging $10bn a year. By November Meta had lost roughly three-fifths of its market…