Overwatch League Teams

Why is every team playing in Overwatch League using the same characters (Winston, Reaper, Sojourn, Lucio, and Kiriko)? There are around 30 characters to choose from and I only see the same 5 characters. Not even Vct is this bad with Chamber.

I leaked the strats so now everybody uses it

They only had like a week to practice on new patch pretty sure

Because its meta and there's pretty much always been main meta or at least strong metas that obviously change based on patches.
Like I haven't really followed OWL so dunno about meta, but my guess and based on interviews:

Sojourn: best hitscan rn with strong damage and good movement
Reaper: strong damage closed range and Kiriko's abilities buff all Reaper's weaknesses. Allows Reaper to kind of be like in old deathball meta. Also counters Winston funnily.
Winston: actually don't know, but good engage abilities and AOE damage so easy ult charge in hectic fights?
Lucio: speed boost really good in OW2 and boops are good vs Winston and even Reaper
Kiriko: good healing, has immortality grenade thing that is good and her ult is really good with coordinated teams. Also can escape easily.

just my guess and Reaper thing was from pro player. Pretty much just strong comp that is hard to counter with different comp until teams come with other ideas or there's nerfs/buffs.