1. Curation is important both for the physical limits (venues only fit a certain number of people), attention limits (attendees will usually retain only a handful of "nuggets" no matter how packed the agenda is) and interaction limits (you can't meet everyone at a large conference).
2. If the goal of a conference is not just to "stamp" research as somehow "approved", but to encourage discovery and knowledge exchange that deepens a specific area, it's important to apply that curation filter with an eye toward best advancing the goals of the conference. That means not just going for things that are okay, but those that best resonate with other presentations / attendees / research topics.
3. While the size of any one conference has to be fixed, tech has made it infinitely easier to create new conferences and journals with other focus areas. They may not start with the prestige of a larger journal, but if the papers published start to have an impact, it can catalyze an entire subfield of work.
Some conferences can be tied exclusively to "novelty" - ACM academic conferences - but others to "incremental advancements" - the bigger industry conferences in security, like Usenix Security and some to "best explaining ideas" - like Enigma.
There are new ways to find an audience for your work and create impact - that's part of the job now.