Admittedly radical, but if we want to have a representative cast of the parliaments the most honest approach.
How about more direct democracy? Representative democracy is a compromise for an era when the will of the people was practically too challenging to collect - something which has been solved in large part by social media. Perhaps the problems described by the author of the article is precisely the tension between a legacy system, made obsolete by new communication technology. If this is the case, we need to embrace more technology, not less and really lean into it. Maybe we could do a geo-fenced direct democracy for example?
Still the effort is brutal and requires full-time. So we need professionals (for a period), because we also need the lesser motivated people's views.
Social media (as is today) is to fragile, to toxic, to susceptible to surveillance and censorship, to centralised and to non-inclusive (in sum: non convival) to be even helpful.
The issue in this case is how we select our representatives, which I agree seems to be unrepresentative and even dynastic. The solution would require refactor of the system though, not a defence of it as the author implies in his article. It is not so much 'social media is undermining democracy' as much as social media is exposing a democratic system, which is in need of reform'