Other posters have pointed out that a semiconductor company does not build a successful business model based on selling to hobbyists.Possible, but just claiming that without bringing evidence does not weight too much.
Yes, the Atmel AVR processor is used in all different kinds of applications, commercial and industrial. I'm not at liberty to discuss specific customers, or numbers, but they are definitely used by professional embedded systems.A similar topic, opened last year, ran for a few dozens posts without demonstrating that 8 bit AVRs have indeed industrial applications.
Look, I work for Atmel. I know what kinds of applications they are in, what kinds of customers. Also, anyone who works in the industry knows that there is not a semiconductor company in existence, past or present, that *only* sells to hobbyists. To argue otherwise, and insist on proof, shows a profound ignorance of the industry and economics. I don't need to prove anything. Available data can be found on the internet.
Because I work for Atmel, as I said, I'm not a liberty to discuss specific customers, or financial numbers. But I can tell you that I've been a software engineer for 21 years, and worked in embedded systems for the last 18 years. At a previous employer, we used the AVR (ATmega128) to design an industrial RFID reader for the pharmaceutical laboratory industry. We also used it internally to do IC (integrated circuit) testing in a wafer test probe for the custom IC that we designed.
If anyone desires further anecdotal evidence, then please feel free to post the question on AVR Freaks, and let the many embedded systems engineers tell you how they have used the AVR in real products that get sold.
I'm glad you find working with the Arduino exciting and fun. If you want to build a robust system, it definitely can be done as there are many people who are doing it.