Why is the gametophyte generation dominant in mosses and liverworts?

In bryophytes—a group that includes mosses and liverworts—the gametophyte generation is considered dominant because it is the long-lived, conspicuous, and photosynthetically independent phase of the life cycle.12

Unlike vascular plants, where the sporophyte is the dominant, independent generation, the bryophyte sporophyte is typically dependent on the gametophyte for nutrition, forming an intimate physical connection with it. Throughout the course of plant evolution, the gametophyte stage has become progressively reduced in more complex plant groups, while the sporophyte stage has become increasingly dominant. In mosses and liverworts, the gametophyte remains the primary stage, responsible for producing gametes and supporting the development of the dependent sporophyte.13452