I've written before about some of the opponents Khabib's beaten in his earlier career:
He beat
Oleg Bagov who's a multiple time Russian Combat Sambo champion, 3x Russian UWW Grappling champion,
2011 UWW World Grappling champion,
2013 World Combat Games gold medalist. He placed
3rd just this year alone at FIAS Russian Combat Sambo championships, all while he's an active MMA fighter.
He beat
Vadim Sandulsky, who's a multiple time Moldova Combat Sambo champ, decorated in Judo.
He beat
Eldar Eldarov, multiple time Russian Combat Sambo champ and World medalist. Now works as the national coach for MMA in Bahrain.
He beat
Shahbulat Shamlaev, winner of the Bellator 2012 Featherweight Tournament, decorated in Sanda.
These aren't taxi drivers. These are guys who legit trained for martial arts their entire life. The Russian MMA scene is filled with talent with extensive amateur backgrounds. People try to downplay the guys Khabib fought. Assuming all his opponents records are even well-recorded (Many fighters from Asia/Russia don't have complete FF records). Its not like the UK/Ireland scenes where people watch MMA on TV think its cool and decide to have a go at it. At least in the US, you have wrestling in high school and half the guys getting into MMA have amateur experience.