Java is not outdated. You still need the likes of it if you are building platform independent high performance applications. At the end of the day, it's just another tool in your arsenal.
But I'd still suggest you learn Python, TS etc because those are very helpful in rapid prototyping and quick iterations. AT higher levels, you're not evaluated based on the number of languages you know or frameworks you are familiar with, but rather your solutionising and design capabilities. Learn to design and build systems.
economies of scale will take time to reflect? It's more of a cloud play, so I'd consider this expenditure as CAC. Copilot already has 100M in revenue, and it's only going to grow more cause of the penetration it already has. Optimizations of using smaller language specific models and routing based on projects and all will bring the cost down imo