Supply is not the reason you are seeing so many cross gen games, in fact both PS5 and Series consoles are selling better than last gen consoles did at the same time. The reason you're seeing so many cross gen games is because it's so easy to program games between these two generations as this is the first time that two console generations share the same architecture. Remember, these cross gen games were in development way before Covid and supply issues. Also, the big three have become more greedy and more focused on profit margin than they ever were before. Some will point to the fact that games are getting more expensive to make, but this point can easily be countered by the fact that games sell better than they ever did before and do so at a higher price this gen.