So I'm seeing this sentence being said a lot and I must say I disagree.
Firstly, the fact that the top guys are in their mid-to-late 30s is a testament to how great they are. Miocic, Reem, Dos Santos, Cain, Werdum are all great fighters. Pretty soon they'll get old and young guys like Ngannou, Blaydes will overtake them. Is normal.
Secondly, I'm tired of people using the Black Beast and Big Country as proof that the division sucks. No it does not. It only shows us what we already know. That sometimes but not always, 'crude' fighters can go far into the sport on sheer toughness and guts. In boxing there was Marciano, at LW there is Gaethje. These guys all have/had a degree of skill to put that toughness to good use.
So relax guys, HW isn't weak.