Space telescope Astronomy research published in Science and Nature:
Ground-based telescopes (31.1%), spacecrafts (27.0%), space telescopes (22.8%). (ref)
Number of professional telescopes affected: >1050. (ref) representing tens of thousands of academic physicists, cosmologists, astronomers and other scientists.
Number of amateur astronomers affected: 200,000 to 500,000 scientifically valuable people
Cost of equipment affected: 30-50 billion of equipment.
Number of Starlinks visible in the night sky to everyday people: more than 100 starlink satellites will be visible to us when we look at the sky after sunset and before morning.
You know how distracting moving lights are, If you look at a sleeping city with thousands of little lights, and 100 planes are flying over the city, it's confusing, you have to look away. The dawn and dusk will soon consist of looking at hundreds of low flying satellites when the first stars start showing up.
1-2 hours after sunset there will still be 20-50 obvious lights still visible, you'll have to look towards the dark side of the sky to only see higher satellites.
Hale bopp, shoemeker-levy, various exoplanets, galaxies and solar system events were discovered by hobby astronomers, and just two terrestrial telescopes on their own have found 5700 asteroids, comets, variable stars and other stellar object (Pan Starrs).
The research states 0.01 starlink lights per square degree, 1-3% of photos for narrow field telescopes will messed up at dawn/dusk, and maximum 30-40% of photos for a wide field 1 billion telescope being currently built.
You won't be able to use Starlink on any mobile phones without 5kgs of lithium batteries and a dish ( >90W Starlink / <1W 4g ), it costs 1500 euros in Europe for the first year (83 per month + 400 equipment) compared to faster fiber at 300 euros. 99.9% of developed populations already have 4g internet at home, while poor nations can't afford Starlink... no monthly prices have been announced for India or African countries.
Is it necessary? Perhaps it will be a 10 billion dollar flop because 40 million yearly customers are necessary at prices exceeding ADSL/4g/fiber and pre-orders are currently low (50k out of 40 million?).