They have very, very different business models. Constellation size is meaningless on its own, you have to account for the satellites capabilities, orbits, and the number and needs of your customers.

This is true at 500km altitude, but not so at higher LEO altitudes.

Arianespace is only building and operating launchers. Airbus is also the biggest satellite manufacturer in Europe. They’re in crisis right now, same as their direct European competitor Thales Alenia Space, due to Starlink destroying the traditional space Telecom market, of which they were leaders.

Ironically, the n°1 helicopter manufacturer in the world is a French company.