The Renaissance/much of modern science originated in Italy, not in England (thus, e.g. Galileo, da Vinci, etc.) And the Italian city-states of the time were fairly free: Pisa, Milan, Arezzo, Lucca, Bologna, Siena, Florence, and Venice were all at some point governed by elected officials. They were also remarkably meritocratic: as the influential Neapolitan defender of atomism Francesco D'Andrea put it, describing Naples:

There is no city in the world where merit is more recognized and where a man who has no other asset than his own worth can rise to high office and great wealth.

(Even if he's only boasting about his own city-state, it's significant that meritocracy was considered worth boasting about.)

Similarly, merchants, not priests, politicians, etc. were considered the highest status group: nobles up to and including national leaders (e.g. the Doge of Venice) dressed like merchants.

(Incidentally, the other factors you mentioned below also played a role: competition between city-states and the influence of outside science from Byzantium and the Islamic world showing what could be done. Nevertheless, Italian freedoms were also necessary: e.g. Galileo was only able to publish his ideas because he lived in the free Republic of Venice, where Jesuits were banned and open inquiry encouraged; he was persecuted and forced to recant his theories when he moved to Tuscany.)