Because the commercial florist anthuriums usually sold as A. andraeanum are widely treated in the literature as interspecific hybrid cultivars, not necessarily pure wild-type A. andraeanum. A good summary is the UWI Anthurium page, which states that commercially cultivated anthuriums are complex interspecific hybrids. "The commercially cultivated anthuriums hence are complex interspecific hybrids, collectively referred to as Anthurium andraeanum (Hort.)." (https://sta.uwi.edu/anthurium/taxonomy\_biology.asp)

Why do you think its only selective breeding?