Minor correction, the first BASIC was for the MITS Altair 8800 which had an Intel 8080 CPU.
Minor correction, the first BASIC was for the GE-235. The Altair was the first home computer to have a version of BASIC, but BASIC had already been around for a decade before it was ported over.
There are a couple things others touch on, but to expand on a few things:
1. Microsoft was formed for developers in the first place. It's first product was BASIC (for MOS 6502). Developer productivity has always been a part of Microsoft's long term vision of itself. It is entirely possible for VSCode to be developed solely to give developers warm fuzzies and for that to fit Microsoft's long term vision.
2. VSCode gently encourages you to explore other Microsoft tools and services. It's built in Typescript and makes cross-platform .NET a reality and has some useful Azure integration extensions to help you run things on Azure services. Part of the delight to VSCode is that it doesn't hard sell any of those: it offers them as opt-in tools and lets you explore them yourself. (Opinion: This is a wonderful sort of return to confidence from Microsoft that their developer tools nearly sell themselves on their own merits, Microsoft doesn't need to hard sell them.)
3. VSCode is "made out of Azure". Part of why VSCode has seemed so effortless to build was that a lot of the core pieces (particularly the Monaco code editor at the heart of VSCode was built for Azure, then reused by IE/Edge Dev Tools, VSTS, before being brought into its own in VSCode) were built for Azure itself to provide a nice development/devops environment experience in the cloud. That seems a pretty good advertisement for something like Azure when even the systems built to support the services offered are strong development tools of their own merit.