A friend had a mid-1990s Iron Horse with a blown-out Marzocchi fork. After brief consideration of rebuilding or replacing the suspension fork, he went for a basic rigid fork.
Step one: prepare the mechanic.
The frame has some classic 1990s bullshit frame details
"Innovation" was the word of the decade. Setting aside the innovations that were actually from the 1890s, there was a lot of weird looking stuff marketed as technical advancement. Before the suspension revolution obliterated the old world, mountain bikes were a lot like any bike. They started out as beater bikes, after all. So the facade of innovation was decorated with tweaks to the traditional diamond frame, some of which did enhance strength and performance. Others either did nothing or were outright wrong turns. In any case, their days were numbered, as the spring-and-linkage crowd worked in their secret labs on the new species that would change the sport forever.
With a fork in it, it's done.
The new mountain bikes can take more pounding and eat up gnarlier terrain, at the cost of more moving parts and more systems to maintain: hydraulic brakes, pivots pivots pivots, shock absorbers, seals seals seals... Yes, the riding experience is either more comfortable or more rad. You also need a heftier budget in both money and time to keep one in top shape...or even just functional. Or you can ride it into the ground, as many people do, and replace it -- or abandon the activity -- when the bike finally fails completely.