At least with Visual Studio, it’s 32bit for performance reasons (32bit is faster).<p><a href="https://www.infoq.com/news/2016/01/VS-64-bit" rel="nofollow">https://www.infoq.com/news/2016/01/VS-64-bit</a>
Given you mentioned Steam, Kerbal Space Program is a great example here. They initially released a 64-bit edition due to community pressure.
It was full of bugs and crashed a lot, and all they got were complaints about a lack of QA. There were mod authors who actually introduced checks and had their mods refuse to run on a 64 bit build, because they didn't want their mods running on unreliable systems.