In every country, people have common names for a handful of animal and plant species that they encounter. Children are taught the words cat, dog, eagle, and carrot, and these truly are common names -- used very widely, not just recent inventions used only by a few people. They are short common names, each of one word.
There aren't such one-word common names for all the animal and plant species that people may encounter. Even in the paragraph above we run into problems: there are three species of eagles in America north of Mexico, and they are called bald eagle, golden eagle, and white-tailed eagle. Although there are just three species of eagles, someone decided that one of them needs a 3-word name. There are about 650 bird species in America north of Mexico. US Ornithologists decided to give each of them an English-language name, and to standardize these names. For one of them, someone invented the name "northern beardless-tyrannulet." Clearly that name is an invention by an English-speaking bird watcher rather than a name that Mexican farmers (its range extends just over the border from Mexico) had been using. So, it is a vernacular name, which means "in the language of day-to-day communication." Few people other than bird watchers will ever have heard that name, which hardly makes it a common name!
There are over 100,000 insect species in America north of Mexico! Few have vernacular names, and even fewer have common names. Three-word names have been invented for some birds. To give 100,000 insects vernacular names would demand names of 5, 6, or even more words for many of them to give these names any meaning in English.
A committee of the Entomological Society of America is charged with approving vernacular names for insects. The committee calls these "common" names, but some are not at all common. Few such names have yet been approved. A weevil species that arrived in Florida soon got labelled (by Floridians) "Apopka weevil" because it was first reported (in Florida) from Apopka. But the ESA committee decided it should be called "West Indian sugarcane rootstalk weevil borer" -- quite a mouthful -- although it had been known in Puerto Rico as "vaquita." Another insect from the West Indies received the name "West Indian sugarcane delphacid" although it had been known for at least 200 years in Jamaica as "canefly", which is a true English-language common name [note: this insect is not a fly, but neither is butterfly].
Common names seldom get used in more than one country. Where they do so, they may get applied to different species -- the bird that is called robin in England is not the species that later got called robin in the USA. Common (folkloric) names may be used only in a small part of one country -- being replaced by other names in other parts of the same country. And they rarely get transferred from one language to another.
So what is the point of inventing vernacular names for the 99,000 insect species in America north of Mexico that don't already have them? They would not be useful outside the USA -- they would mean nothing on the other side of our border with Mexico, for example. Many of them would consist of 5, 6, or more words and be hard to remember. And, how would we create US "common" names for the several million insect species that exist in other parts of the world? Better to stick with the 2-word scientific names (SECTION 6.4) that are valid worldwide.
Some non-biologists don't want to use scientific names for insects -- they want a short, "common" name. But, to expect a short, common name (like cat and dog) for even 100,000 insect species is wishful thinking -- it cannot happen because few such names will ever be common or short -- because there are just too many species to name. If you can pronounce and write Slobodan Milosevic (with accent acute on the "c", see graphic below), you surely can pronounce and write scientific names. If you can pronounce Agave, Allamanda, and Asparagus, you already are using scientific names!