Theoretically, it is possible, but it would take HUGE amount of time. There are plugins that disable movement hacks and Killaura, but also one which disables xray functions. This is big step for preventing hackers.

It's about as easy for Mojang to get rid of issues with hackers as it is for plugin developers. Mojang has anti-fly hacks support to servers, as has Spigot and Bukkit, and it works half the time. Otherwise, hacks like x-ray and aimbot have continued being used. Mojang hasn't done a lot to prevent these since there's not really a way to do so on the client-side; otherwise, they would be removing modding from the game. It's important to remember that "hacks" are actually just modifications, or "mods", to the game. Therefore, the only way to stop them is through plugins. There are a lot of anti-cheat plugins, but they don't always work. In addition, often in the case of anti-aimbot plugins, legitimate players often get "caught" for using hacks even though they weren't doing so at all. That's why it's hard to detect hacks; in terms of coding, there's not an explicitly distinguishable difference between hackers and legit players.