That's just "services", though, and it's been the way that people have been building software for a very long time. I can attest to have done this in 2007 at a large website, which was at least 7 years before the "microservices" hype picked up (https://trends.google.com/trends/explore?date=all&q=microser...). When people say "microservices" they're referring to the model of many more services than what you describe, and the associated infrastructure to manage them.