not particularly. there are plenty of decent teams with great snipers but not elite snipers. imo I don't believe teams need an elite sniper to make it up for an era. also, you dont know how teams work in the game. im not saying i do, but igls are also a massive part of how awpers find their form.
an example of this core firepower not working, or teams defying the elite sniper rule: g2 before jks and hooxi, liquid with nitr0 as awper, and some other examples with teams with not elite snipers with cadian, jame, saffee to name a few
my point is not to say these snipers arent important, but its really not possible to chalk up an era due to saying "ok well NiKo and hunter and m0nesy are just godly so they win everything"
eras are defined by longevity. please realize that we have had very few dominant eras. the only semi recent era we've had is the astralis era, and we are not getting that type of era ever again. the scene is much more competitive, and just comparing rosters awpers will not work.