Any customer of, say, Microsoft, expects updates for Windows. If there was no such promise (implicit or explicit), customers would be much more wary of buying

Any customer of, say, Microsoft, expects updates for Windows. If there was no such promise (implicit or explicit), customers would be much more wary of buying and using Windows. The promise of updates is almost the entire thing nowadays. Anyone can find some random program to solve a problem today, but adapting yourself and your problem to the program has such a high cost that you don’t want to get a new program every time. Therefore, a user wants a program with future updates, so that the adaptation cost is a one-time cost. Updates may or may not cost money, but this is almost irrelevant. Users want to avoid the adaptation costs (and associated effort) of switching to another program.