Was the Sherman Antitrust act sucsessful?

No because for numerous reasons:

1. The act didn't specify which trusts were considered illegal whether they were "good" or "bad" combinations
2. The writing and form of the act has numerous loopholes and vague phrasings that the lawyers from big businesses could exploit and manipulate
3. Labor and craft unions were also made technically made illegal by the Wording which was used by the monopolies and their lawyers would use the act against the unions