My DC are in quite a big high achieving group for literacy in year 6 which contain a lot of boys who also love computer games.
No whole class novels and the phonic provision they had way back was shite.
They do read a huge amount individually and I know computer time is hugely restricted in time and content.They do like some games but all are age appropriate. Interestingly they hate football as do many of their friends.Often after they're booted off screens if nobody else is out playing they read- a lot.
That said they've always read a lot.It's interesting as one was never in the higher group for writing until about a year ago when his spelling,punctuation,h/w etc fell into place.It was never poor but wasn't good iykwim. It feels like having everything sorted he now feels free to focus more on his actual writing technique iykwim.
I think we expect a lot from kids in the early years.Holding and using a pencil competently,spelling,punctuation,grammar and that is all alongside structure and content. I think some boys mature slower and get turned off writing by the huge task to produce what teachers want. I think more girls are happy to and do produce the above quicker so by year 5/6 are steaming ahead.Obviously there must be exceptions to the rule( I have another girl and boy who are both exceptions) but overall I suspect this is the case.
I also think by year 6 having read a huge amount of books,having them in their hands and absorbing the punctuation,imagery,ideas etc must help so reading should be key.
I don't know what you can do though.You can't force parents to boot their kids off screens and to spend money on books instead. Schools can only do so much.I do wonder if gov health adverts highlighting the benefits of reading and recommended screen times would help.