Why are gymnosperms more widespread than higher spore plants?

To answer the question, let us recall what is the main difference between seed (gymnosperms) and spore plants.

1) In seed plants, all groups of tissues are fully formed (in contrast to ferns, mosses, etc., in which they are less developed).

2) The method of reproduction by spores requires the mandatory presence of water, because only in it can they meet. Seed propagation has solved this problem, so gymnosperms are found in drier areas where spore plants cannot thrive.