Just ask yourself honestly if the situation occurred where the captain becomes incapacitated in the cruise at 37,000 ft would the 250 hour first officer be able to safely fly that aircraft solo IMC all the way from cruise to the landing while making all the radio calls to ATC etc. Especially as his company limits him to a max crosswind component of 15 knots.
Perfectly capable. At 250 hrs, completely every single one of them. And all done by the book too.
It depends who trains them, and to what standard are they made to perform.
I am not disputing a narrow field of vision, non-existent experience, nor being just inches ahead of aircraft. But a single handed return to land with a malfunction is a piece of cake. They're young, sharp and motivated..