Berkshire had a pivot where, decades back, Munger convinced Buffett to switch from investing in bad companies at a great price to good companies at a good price. Their new strategy is still active.
That said, the turnaround 'mission' you mention about still happens, but is more associated with private equity than Berkshire.
Not quite right. The pivot was from good companies at a great price to great companies at a good price (unless you can get a great price, but that’s unlikely).
Over the long run the latter is a better and more scalable strategy.
They also have a history of buying good private companies at a good price and then let the management keep cooking. This is especially relevant to family businesses that want liquidity for the heirs and good long-term (indefinite) stewardship rather than selling to some PE vulture that will destroy their legacy.
That said, the turnaround 'mission' you mention about still happens, but is more associated with private equity than Berkshire.