As gaming became more popular, the company struggled to enter the market through their own App Store, as competing products had already captured market share.
In the early 2000s, Apple was more concerned with their suite of creative applications and music software rather than games. The lack of games on Mac wasn’t only due to hardware and software, but also the business model as a whole. Additionally, Windows made it easier for game developers to interface with their hardware using widely supported API tools such as DirectX.
Macs generally didn’t have the same gaming-oriented hardware that Windows PC users enjoyed, such as high-performance CPU chips and video cards.
The main reason for Steam not initially supporting Macs was them containing proprietary hardware that game developers struggled to cater for.