That’s basically how steam does linux support now. There are different runtimes you can target that get frozen and have long term support. The issue is these namespaces/containers/runtimes only became available in late 2019, and meanwhile proton was getting so good and the Linux marketshare is so small that linux steam runtimes didn’t really take off. If Linux market share continues to grow, Valve is ready to support developers building better supported linux native binaries.
Because they’re planning on replacing it with something else that I’m pretty sure will be even shittier. And they’re giving barely no notice before ripping out the rug under people. Nothing is so shitty it can’t get shittier.