21CB is nowhere near their best selling record. American Idiot, Dookie, Nimrod & Insomniac all easily beat 21CB in terms of sales. 21CB has more streams than Nimrod/Insomniac because it's a more recent album
If 21CB is a rehash of older material, then you have to have the same opinion about Insomniac which is similar to Dookie in a lot of ways too. Restless Heart Syndrome and East Jesus Nowhere sound pretty unique to me. Yes, RHS is similar to BOBD in some ways and lyrically shares similarity with Novocaine but it is definitely not a rehash, I think it actually is better than Novocaine in terms of the lyrical content. I don't understand how EJN is similar to Holiday apart from the fact that they both have a bass led section in the middle. The guitars do not sound similar on these songs at all to me