Seems really weird to me to go through the work of having screenings, interviews, accepting an offer and then just ... not show up to work, even if you have another, better job. The interview process is such a bitch that sending an email declining a job is one of the most effortless things about the interview process. I don't 'feel bad' for companies, but it's a pain in the ass for the people who put work in for you to be hired, HR, the manager hiring you, the people on your interview team, etc. Reflects very poorly on the candidate, and this is a pretty dumb thing to do career wise.
This isn't really the equivalent of recruiters not emailing you back or replying to an application. It would be as if a company gives you a job, and then you show up and they just ... don't pay you and don't let you into the building. I used to reply to personally reply to each recruiting message on LinkedIn turning them down 3-4 years ago, but now there's so many in my industry it's just non stop so I don't bother anymore.