Why do you suppose inside fighting seems to be a lost art these days? Most fighters now look completely lost when their opponent clinches them. They don't know how to effectively fight out of it, and instead, rely on the ref to break it up.
Some still can. Ward is known to clinch his opponent's lead hand and then hitting him with the free one (look at Ward vs Green for 12 full rounds of that) and I thought it was strange to see in another thread that Beterbiev was supposed to be bad in that while I see the exact opposite. Knocking fighters down or even out from out of the clinch.
Ricky Hatton was very effective at "Rag-Dolling" opponents on the inside, but got a lot a Flak, even though it was an effective demoralisor,
It's taught more in new gyms to keep your opposition at a distance so you don't get caught and hurt. I like to be close because I have a short arm span and being close helps me with my power shot because my jabs are weak. Most stand outside because they want to pose and look good. A la Broner- weak jabs, strong hooks 69in arm reach. He is an inside fighter copying and outside fighter, just dumb boxing his gym won't correct. Tim Bradley- has not much power but his a great inside fighter- short reach but can adjust and box in and out. Wilder has a great jab like Wlad does but Wilder has a weak hook and zero ability to uppercut(If anybody knows were I can watch a clip of this man throwing an uppercut ,please send it to me)