SEOUL, South Korea — For decades, South Korea has been plagued by corrupt ties between government and big business, a state of affairs that dates to the country’s dictatorial past and persists as it became a global economic powerhouse.

For nearly as long, politicians involved in graft have been going to jail — including those at the very top. In the 1990s, two former presidents convicted of corruption received lengthy prison terms. On Friday, former President Park Geun-hye joined their number as a court sentenced her to 24 years, more than a year after she was impeached and removed from office over an influence-peddling scandal.

But few expect Ms. Park’s punishment alone to bring about a fundamental change.

In South Korea, a president wields what is often characterized as “imperial power” — but only for five years. The country’s most enduring power is the handful of family-controlled conglomerates known as chaebol, which have survived repeated corruption scandals and changes of government and still dominate the economy.

Analysts say the old ways of doing business won’t change until the chaebol are held to account for them.