They won't be able to extend the season, there just isn't time. If the clubs get their 2 week circuit break that they seemingly want (aka Christmas off 😂) they will just have more games to play in the remainder of the season. I then forsee complaints that players are getting injured due to having to play three times a week.
Of course, if other countries also have to suspend their seasons there will have to be discussions around moving the Summer Nations League games and / or The World Cup, but at the moment England are the only of the major nations to have been affected.
There are only two scheduled full midweek programmes in League One and League Two after the New Year. I know postponements and rearranged fixtures will come into it, but there are still around a dozen free midweeks for the lower divisions as we stand.
That said, I want to be playing now, not then, if it's possible.