The concept of a stock buyback is that the company feels it's shares are undervalued compared to what it feels they should trade at. As it's the companies duty to provide the best ROI on the capital the company has to it's shareholders the only time they should be purchasing stock back is when they have an excess of cash and feel the stock is cheaper then it will be in the future. 

The idea of buybacks isn't about controlling price, but rather about creating more value for it's shareholders. 

So a buyback announced when the investing community feels a stock is already to high can be a major negative for a stocks value. It shows poor leadership and lack of forward thinking decision making ability. But one timed when the community feels a company is holding to much cash without a vision to put it to work can be very beneficial to the long term stock value reducing it's supply. 

That all said 100% you could have this in centralized projects, which many coins are. But in a fully decentralized project it wouldn't be achievable. 

In a centralized coin there is a parent company which issues the coins. Pretty much any ICO is not decentralized and could take advantage of this idea of buybacks and reselling. Most of them still own a massive stake of coins which are to be used for future R&D or to pay salaries. This stake is large enough to control the price on any upswing, then later on a down trend they could take those profits to buy back the coins they sold plus some.

A truly decentralized coin which has no central control would not have the ability IMO without a predefined system in place that spells out when price swings would be attempted to be capped. But even with it being predefined you would need to fund it with coins and capital at the onset. Plus hire someone to manage these funds and make sure that the rules are followed....don't forget needing funds to pay this company. You would also need to realize that with predefined rules that pump and dump specialists would be able to manipulate your rules against you. 

So the same rigid set of rules that make sure the companies hired to achieve balance doesn't go against the intentions of the founders are the same rules that can create manipulation by those looking to exploit your rigid trading rules. 

To be clear most coins out there IMO are not actually decentralized and therefor most could take advantage of this.