I wouldn't say there's much of a gap if any at all just based on that. The only stat differential that kind of stands out is the playoff points. 100 in 123 games compared to 53 in 103. Bit of a gap there.
Overall though there's still some variables besides era so it's still not a perfect way to compare, but just looking at the numbers I'm not sure anyone can say that there is much of a gap. Even if the variables were known and taken in to account, at the end of the day they look pretty close still.
If it's the same era, it's too close to call without knowing either player's defensive ability, toughness, leadership, or linemates. But assuming all those are exactly the same, I'd take player A because his playoff numbers are better (assuming player B's numbers aren't weighed down by very few games in his prime and a lot of non-prime games).
You may see Kovalev ranked ahead of Whitney on most player-ranking lists, but I would take Whitney on my team ahead of Kovalev any day. Except for some of those days Kovalev decided to give a damn. But Kovalev is a wheelbarrow and Whitney is the guy that grabs the wheelbarrow and goes to work without hesitating. No not in that way.
Trying to answer this without looking at the multitude of posts that have divulged the identities...
I know that the first statline is Kovalev. So I am guessing that this comparison is meant to show how Kovalev is statistically similar to some other "scrub" despite having a much better reputation (of course, that reputation being almost solely build of his offensive contribution), thereby bringing into question the reputation itself.
Kovalev looks to have the clearly superior playoff numbers, though he did play for some high-octane teams. Also, player B's statline kind of looks like that of a compiler to me..no 90+ point seasons. Again, if he is a defensive stalwart then it changes things...but you likely would have mentioned that. Still, some kind of context (teammates, ice time, games played) would be needed.
Lastly, I'll finish off by saying that Kovalev's reputation was gained through watching him. His ability to take over games was (is?) unquestionable.