Who is 'we'? Large parts of the world are fine with partially effective vaccines. India does mandatory BCG vaccination for tuberculosis despite a fairly low efficacy. The goals with vaccination cannot be 100% effectiveness because viruses and bacteria mutate, and well, people themselves change. What may be effective in children may not be that effective in oldies. The immunity usually wanes with time at different rates in different people. The aim of vaccination is often to bring r_0 under 1. Thus, any outbreak will die down rather than spread. Vaccines themselves, can and do have terrible side effects at a low rate. It is about balancing all these objectives.
Somehow COViD has changed a lot of people's ideas on what vaccines can do. Mandatory vaccination for a range of conditions has always been there for traveling to many parts of the world with endemic diseases. COViD is just another addition to the list, not the first disease against which vaccination is required.