Back then, people couldn't find them anywhere else because the government shut down any other store that tried to sell them above their approved, fixed price. They allowed Traki a monopoly over diapers and graciously looked the other way.
They didn't "shut down", they rightfully forced criminal store owners to stop fabricated inflation and sabotage, as many companies did in Venezuela and still do. The main reason why a precise selection of products was hard to find (bastards). Millions of Venezuelans ask the government to be even more tough in fighting price manipulation crime, which is one of the most horrendous crimes of the economic war.
The government is criticised if the act (by the opposition mafia) and is criticised if they don't (by the people, who are right).