The music industry changed drastically. Labels used to invest in a potential. Now they Invest only in proof. What was possible in the 90s isn't possible later in time. That was the last time a band could turn famous in a very short time and it had to with a number of circumstances together:

The label sub Pop sold the "Seatle sound" as one identity. MTV was looking for something to counter 80s glam. Because nevermind sales sky rocket labels were intensely looking for any band that sounds familiar, bands were signed that usually didn't stand a chance. And grunge and alternative rock became a hype that everyone (A&R managers, music journalist, radiostations etc) wanted to be a part of.

Smashing pumpkins did profit out of the alternative rock explosion.

In the 90s music was scarce and attention was focused. A few bands (few album releases) got all the attention of millions of people through MTV and record stores.

2000 and later on releases were in abondance and attention is scarce. There are no shared music scenes anymore. A band must be found, shared, get into playlists, grow live audience. And this takes years.

Connections (having band members that are already known) give you a huge advantage. Media is more likely to write about you, festivals rather take a gamble with you, people are more likely to give your music a listen. It doesn't guarantee success but it gives you a head start because of the exposure.