Savannah Phillips, Isla Phillips, Mia Tindall, Lena Tindall [great-grandchildren] and Lady Louise Windsor & James, Viscount Severn [grandchildren] are not mentioned either. Archie is not the only one excluded. One can support the Sussexes without bashing or making cynical/snide comments on the Royal Family
George, Charlotte and Louis are children of the future king, senior working royal members and are most likely to be expected to have more prominent public roles in the future. Savannah, Isla, Mia and Lena are not children of senior working royal nor expected to become working royals in future. Lady Louise Windsor and James, Viscount Severn will most likely choose their career path and probably not use their HRH Prince/Princess titles when they both turn 18. Their parents (Peter Phillips, Autumn Phillips, Zara Tindall, Mike Tindall and Earl & Countess of Wessex) probably wants them to have little public roles possible, apart from major royal family appearances (Trooping of the Colour, Christmas in Sandringham, weddings , photos celebrating major milestone- Queen's 90th birthday etc.). Baby Brooksbank probably would raise in similar ways to the children of the Wessexes, Phillips and Tindalls rather than the Cambridges.
I'm sure The Queen and Prince Philip loves all her great-grandchildren dearly, regardless of external circumstances. Just look at Princess Beatrice and Princess Eugenie's relationship with The Queen and Prince Philip, despite tension between the princesses' parents and Prince Philip (mostly Sarah and Philip). Perhaps (in my opinion) The Queen agrees with wishes of the Phillips and Tindalls for not focusing on the cards send by Savannah, Isla, Mia and Lena, given that they are most likely to live private citizens and not wanting extra attention.
The Royal Family has released the picture on their twitter account. The post did mention Prince George, Princess Charlotte and Prince Louis.
The Royal Family @RoyalFamily
The Queen and The Duke of Edinburgh look at an anniversary card made by Prince George, Princess Charlotte and Prince Louis, alongside other cards and letters sent by well-wishers to celebrate their 73rd wedding anniversary tomorrow.
[Camera with flash] Chris Jackson/Getty images
9:02 AM · Nov 20, 2020·Twitter for iPhone
I agree with you suztav, some of the Sussex Squad members have been acting ridiculously, especially after the Queen's Christmas speech last year and the photo of the line of succession. Mind you, this isn't their worst behaviour