What airline lets you book a flight two years in advance? If you could your flight would most likely change 20 times before you took off. There is a sweet spot for airfare and cars it's usually about 2-4 months out. WDW doesn't release discounts more than a few months in advance and booking cruises on opening day seems to be of little benefit right now.
Virgin has their own '
travel agent' branch called Virgin Holiday. The flights are within their company, they tend to have their own pattern so mostly can predict with high accuracy the flights they are planning, sure times may change a little but never really anything drastic, British Airways does something similar online.
If I wanted to book flight and hotel (possibly even park tickets) with Virgin Holidays I can do so atm until end Dec 27/Early Jan 28. Same for Fly drives (though these tend to be more expensive then seperate and you have to go with the provider they choose which I think is Hertz and not someone we would choose to go with). If we wanted to do a WDW onsite stay, that booking period is reduced to Dec 26/Jan 27, and includes the 'free' dining offer.
If booking flights only, 11 months is the max. Obviously I cant compare the same dates at different time lengths for the purpose of this comment, but comparing a flights 3 months from now to one in 11 months, the flights are comparable. About £100 cheaper give or take depending on the cabin (400 for upper class) 11 months out than they are in 3 months time. Same for 4 months, though the price difference for Upper class is only 200 instead of 400.
Booking short notice might work for you and others, but it doesn't work for everyone. Between different circumstance, job flexibility for leave, and personality (I.e preferring to know a cost and have it confirmed, rather then have to keep checking, tracking and maybe miss out because you had a busy week and it skipped your mind) it does not work for everyone. To each their own.
ETA: re booking opening day having "little worth", again thats a personal opinion and depends on personal circumstance. Alot of the discounts offered are either restricted to residency (Florida and Canada) which doesn't benefit a lot of cruisers, or are GT cabins which also doesn't benefit everyone as some people can't take the gamble on placement, some also need accessible cabins which of which are not many. The 3rd and 4th guest offer only benefits familys/sailing parties of 3 or 4, so again not everyone. And some people have placeholders. People can put a deposit down and if a offer comes out that works out better before PIF cancel and rebook, or apply the offer retrospectively is allowed like the recent offer was. There is no loss, in my veiw at least, to putting a deposit down and locking in the price. If the price decreases for some reason, you call disney and they sort it out for you (have done this before).
We've probably planned out up to 18 months (depending on the vacation) but I don't think that we've been able to go out two years. I've got us through the end of 2026 and just not so patiently waiting on the next 
