I'll add that radio manufacturers tend to look at it as "markets" or "verticals".
"business use" - Retail, light industrial, hospitality. Usually minimal features, basic user interface, light duty, low or no water resistance ratings, often "pre-programmed" or pre-programmed channels you choose from. Usually designed to be "idiot proof", as in minimal controls that an inexperienced user can mess up, primarily will have on/off-volume control, push to talk button. Maybe a channel selector and an option button or two. Single pin or two pin audio connectors, if any. Slightly above the consumer grade radios (FRS/GMRS, etc.). Built in battery (maybe), 1/2 - 2 watts.
"light industrial" - Construction, warehouse, hospital, educational, security. A few more features, more user accessible controls, more channels. Maybe trunking capable. Generally a slightly more durable radio, a bit of drop resistance, maybe some splash/rain proof ratings, interchangeable batteries for extended run time, 2 - 5 watts.
"Industrial" - Heavy construction, facility maintenance, education, hospitals, security, transportation, petro-chemical etc. More features, more robust design, maybe display and more option buttons. Usually have higher water resistance, dust ratings. Single/dual pin audio, or multi-pin audio connectors. Might have IS/ATEX ratings for explosive atmosphere, might have basic encryption/scrambling. Trunking, etc.
"Heavy industrial/Public safety" - Heavy industrial use, manufacturing, police, fire, EMS, etc. These radios usually have a higher level of dust/water intrusion ratings. Often really designed to get beat up, every day/shift use. Higher tier encryption, AES/DES, etc. Sometimes submersible rating (1 meter/30 minutes), IS/ATEX, high duration batteries, multi-pin accessory connectors, option ports,over the air programming, trunking/P25, display, full keypad, encryption, etc. Large selection of options, GPS integration, GPS speaker mics, headsets, heavy duty cases. These are often the types of radios you can use a wheel chocks, batons, self defense, perpetrator subduing, etc. Going to be expensive, but designed for years/decade of constant use. Police officer proof, etc.
"Higher end public safety/military" - Fire fighting use. While law enforcement likes to think they are the most demanding radio users, it's usually fire agencies that have higher requirements. Often IS/ATEX is a requirement, as in they can be used in an explosive atmosphere. Long run time batteries, over the air programming, over the air rekeying, blue tooth, microSD, voice announce, fully submersible, hundreds of features, display, full keypad, encryption AES/DES or higher, trunking, P25, lots of channel capacity for interoperability, over the air rekeying of encryption, huge range of accessories, often cost thousands of dollars to ten thousand each. "AKA - Taxpayer funded radios", as in "money is no object".
Basic idea of how the market is set up.
Down near the lower tier stuff, there are a lot of manufacturers, including many of the low end Chinese. As you move up towards the higher end stuff, there are few manufacturers, mostly US/Canadian/Western Europe.
And before anyone starts an argument, this is just a basic example, not intended to be a complete and exhaustive list. Just trying to give the new guy an idea…..