Nothing can be done about Destiny but Bungie can do a lot more with the sequel as far as older content goes.
We’ve known for a while that Bungie wants the Destiny franchise to be something that players will have an interest in for a decade. One way the company can actually make sure the game’s players are going to indeed be roped in is to make sure that the sequel supports older content as Bungie add new ones, unlike Destiny. The number of players who are voicing that opinion is only growing and it seems as though this is one of those things Bungie needs to listen to very closely.
One Reddit user merkwerk recently started a thread where he basically flat out asked Bungie to make expansions for Destiny 2 (whenever it launches) to be more of an addition to the universe that will be present in the game. But some may say that this is how MMO works and replacing old content is fine. But since Destiny isn’t really a fully fledged MMO and it only resembles the genre in some ways, Bungie does not need to emulate the genre. This is because raids in Destiny may take anywhere from a day to a week for a player to finish whereas raids in proper MMOs such as World of Warcraft may take weeks.
This kind of approach will certainly help whenever there is a content drought. Old content would still be relevant and players will have more to do every time they play the game. With Destiny 2 not coming out until next year, Bungie is promising a big expansion this year. What that expansion will bring is anyone’s guess but we are not expecting Bungie will make older content relevant again whenever that expansion lands.