This involves two things.
1. Low cost (definitely less than 50k. Preferable less than 25k). This makes the barrier of entry low and there will be people who say "I don't know if it's worth it but what the heck, let's try
it anyway. It doesn't cost much."
2. A tangible gain from coming. We cannot piss off the high paying sponsors who will have booth and other things at the event. However, just paying 10k or something and having a link on the website
doesn't do much. A startup row which will be active from (say) 14:00 to 17:00 on the first day where the startups can all be in one room with a row of tables. They can pitch their wares, organise
little contests or whatever during that time. It won't be exclusive but will be along with other talks.