surely players can afford some sort of security to prevent this from happening
They are easy targets. Make big coin. Live on big estates generally where every Tom Dick and Harry know where they are. And even better, if you want to know if the owner is home, look up the team list for the next game.
Its why big money UK people either live in London where you can control the environment or so far off the beaten track that to get there someone is noticing on the way in.
Grealish lives on an estate in Cheshire. Too easy to get in and out. He had security dogs, panic buttons and apparently cops were on the scene in 10 mins with dogs and choppers. And got no one. The guys doing this are pros.