A more in depth explanation about trichome development.
Trichomes are formed as a protective layer to the plant. The way they were bred can simply be about trichome production or better phrased trichome production can be caused by mainly genetics, but other factors as well.
These other factors would be when it gets to hot, to help again protect the plant. Certain strains will show differences due to the phenotypes and genotypes also dominant and recessive alleles. This has to do with how plants grow vegitatively, as well as give off visual traits such leaf pattern and shape, and then visual traits in flower that it gives off is bud structure and development, trichome production, color, smell, taste, and overall appearance. This can also be why you experience different highs from the same strain.
Then pests also contribute to this factor if you have pests around they will form a thicker layer in order to protect them self do to the oils and terpines the plants emit as well as the resinous material it contains (the thc). Not saying pests are a good thing they are bad lol.
Humidity and temps can also play a big factor in trichome production so safe to say (a proper and healthy growing climate they can thrive in).
I hope this information helps it was a stretch remembering this lol @mantas