Why Japan's shipyards do not immediately yield a supercarrier

If Japan can build giant commercial ships, why could it not simply build a supercarrier?

Large shipyards provide capacity, but carrier-specific design and operating experience must be rebuilt gradually, probably through larger successors to the Izumo class.

The ability to build very large merchant ships does not automatically preserve the industrial knowledge needed for aircraft carriers. Japanese industry was destroyed and rebuilt after the Second World War, followed by a long break in carrier construction. The Izumo class begins restoring relevant experience, so later successors could become larger and more capable. An evolutionary step toward roughly the 35,000- to 40,000-ton range is presented as more likely than an immediate leap to a supercarrier.