In the current world where most of the forum discussion happen on Reddit, there is little space left for another active centralized forum.

I strongly disagree, and there are tons of other centralized forums that are doing just fine. They’re not as big as Reddit but some have an order of magnitude (at least) more users than Lemmy does.

The decentralized approach has at least the pro to offer something different (you can leave for another instance instead of depending on a single corporation for access).

There are lots of ways to offer something different, and new upstarts have been able to gain traction by offering something different countless times in the past.

Especially if we’re talking about a forum for the masses with a high number of users, the vast majority of those users simply don’t care about centralization vs federation.