There were at least three main reasons why the strikes of the 1890s did not really help workers in the long term (or even, usually, in the short term). Two reasons had to do with what the workers’ opponents were willing to do. The other had to do with supply and demand.
The strikers of the 1890s faced serious opposition. One source of opposition was the employers. Employers were willing to do a lot to oppose strikes. Two of the most important things they would do were to employ strikebreakers and to employ “detectives” who were willing to commit acts of violence against the strikers. Examples of both of these can be seen in the Homestead Strike of 1892 (with the armed Pinkertons) and the Pullman Strike of 1894 (strikebreakers hired to put the trains together).
A second source of opposition was the government. The government was anti-union at this point in history. It did things like issuing injunctions against strikes using the Sherman Antitrust Act. It was also willing to send in troops to break strikes, as happened in the Pullman Strike.
Finally, however, the strikers encountered supply and demand problems. The work they did was simply not skilled enough to sustain strikes. There was a huge supply of workers that could replace any strikers or union members. With supply outstripping demand, employers enjoyed a “buyer’s market” in which they could break strikes relatively easily by finding other people to hire in place of the strikers.
For all of these reasons, the strikes of the 1890s were not very beneficial to the cause of the workers.