there is already a number of space station replacements in progress, including NASA funded axiom. the intent is that NASA will become a Tennant on a commercial

there is already a number of space station replacements in progress, including NASA funded axiom. the intent is that NASA will become a Tennant on a commercial station or two, and be a customer of commercial transport to and from those stations. dragon, starliner, and dream chaser all plan on serving the iss until retirement, as well as private stations well after it's retirement. NASA and ESA don't plan on stopping their LEO work when the iss is retired, they just plan on stopping the development and maintenance of LEO transport and stations.