The fact that more countries are joining BRICS and even more are showing interest to join, shows that there are a lot of benefits in dedollarisation and the multipolar world and they all see it. In the future, the members can definitely change. Some may go away seeking interests elsewhere, some can be kicked out as dead weight, some new members can join but everything will be constantly changing until the World Order is finally established. That's the nature of transitional phase. In fact this is one of the reasons why BRICS is moving ahead not as fast as we hope.
Oil is what has made the USD stronger over the years (aka Petro Dollar). Maybe BRICS will come up with a unified (single) currency backed by Oil? Or maybe Gold while they're at it? Only then, the bloc will become a "force to reckon with". Some say that US President Donald Trump's tariff threats against BRICS are only driven by fear. In other words, Trump is nervous of how BRICS is quickly gaining traction.
Will the bloc succeed? Only time will tell. The EU, although weak, is also a bloc that cannot be underestimated. Either way, multi-polarism is inevitable now. It could've been worse, right?