An automatic loom manufacture got turned into one of the biggest automobile companies: Toyota
Nokia was initially a pulp mill.
Microsoft initially sold a BASIC interpreter, then a Unix, then MS-DOS.
Panasonic started out making lightbulb sockets.
Mitsubishi started as a shipping company.
To your broader point, though, it's true that most of the major Japanese conglomerates have amusing/modest origins and have accrued side-businesses over time until they became goliaths.
It's still interesting that a company like Panasonic began with something so mundane. Other than a few cases like IBM (which began as separate companies making time clocks and card punchers), it's not that common a story in the western market.
He didn’t found Berkshire he just bought a old public not very healthy textile company and used it as his investment vehicle /holding company and dumped its assets.
The kind of change that Berkshire Hathaway went through is fairly well used tool in finance. Every SPAC does the kind of the same for example, asset stripping and selling in parts or becoming a holding company is natural way for companies in late stage to die.[1]
Alphabet becoming a holding company is perhaps closer to a pivot for holding and operating companies than Berkshire
[1] A recent example would be Altaba that was created from the remnants of Yahoo.
The Nokia plc we all know mostly focuses on wired and wireless network technology.