Male contraceptives are difficult to approve to begin with, specifically because there's no political will to expedite anything that benefits males as a sex. They don't need to go after this sort of thing until something actually gets approved.

The FDA also requires tighter standards regarding side effects because they do not prevent or treat a condition that the patient has (because pregnancy is not a concern for male persons). If you ever hear someone talking about a male pill and implying that the guys in the study couldn't deal with relatively minor side effects, it wasn't the patients that ended the study and it wasn't because patients were unwilling to continue using it.

There was also a pill derived from cotton plants, but it had two major issues: The first was that the difference between a contraceptive dose and a toxic dose was too small to be comfortable. The second was that sometimes (but not always) the effect was permanent.

There's also a technology developed in India for a sort of reversible vasectomy that requires an injection of a polymer in each vas. It started out as an attempt at an artificial heart design, in the 70s was used as the basis for a water pump, and still later became the basis for the contraceptive. US IP rights to it were bought by a US company in 2011, and a slightly different formulation of it was in testing until 2023 under the name Vasalgel (which proved less reversible than the original). The rights were bought by a different company in 2023 who are looking to try to bring it to market under the name Plan A For Men.