Code converts to an open-source license after X (e.g. 4) years in BSL. Time will tell how it works out, especially for mature products it could just mean that everyone targets the 4 year old version.

Time will also tell how eg. SSPL will work if eg. Elastic becomes bankrupt, what happens if I can't get a commercial license for it anymore in 10-20 years? BSL:s expire clause ensures that old code never gets unavailable because the business entity has vanished. Does SSPL have any similar protection?