Depends on the user. Basic LaTeX2e/LuaTeX can be learned over 5 days. Guru level like any programming language needs its 10K hours. There are people who have an aversion for backlashes. The main reason for the "\" is perhaps the only char that is not commonly found in texts. Others like ":" re very common in texts. When parsing LaTeX and behind it is Knuth's original TeX engine, the commands are swimming in a sea of text (as the Dragon book says).