It’s unfortunate, but the different vaccine trials all have different demographics and different measures of efficacy. IIRC, the Moderna “95%” is not “only 5% developed COVID” but rather “95% didn’t end up showing any symptoms” while AstraZeneca was doing weekly testing (again this is from memory). With so many people being asymptomatic, the difference between “95%” and “66%” is in the details (which is definitely why Johnson and Johnson also highlight their 72% in the US, and 85% against hospitalization/death).
tl;dr: each vaccine group made reasonable, independent choices for their effectiveness metrics, but they’re not the same metric.
[1] https://www.jnj.com/johnson-johnson-announces-single-shot-ja...
[2] https://www.jnj.com/coronavirus/covid-19-phase-3-study-clini...