What historians generally say is that the emperors of the Sui Dynasty (like its founder Yang Jian, were overly ambitious and tried to accomplish too much in too short a period of time.  When they did this, they accomplished a great deal, but in doing so made their subjects angry enough to rebel and overthrow them.  Their accomplishments did not really help them, but they did help the Tang dynasty.

An exaple of this was the building of the Grand Canal linking the Yellow River and the Yangtze.  By building this, the Sui Dynasty helped to build a foundation for later prosperity in China.  This helped the Tang Dynasty last for centuries.  The problem was that the forced labor needed for that and other projects made people so unhappy with the dynasty that they eventually rebelled.