You have never organized a moderate or large conference. Your list doesn&#x27;t even cover all major areas. No logistics? No electricity, network and video recording? None of the legally-required (depending on venue + number of attendees) professional personnel (event technicians, medical, fire, maybe an electrician. optionally security, cleaners). Not even insurance? Not even gaffer tape (not kidding, it&#x27;s expensive)! (And I&#x27;m assuming your volunteers have enough time for all the time-intensive tasks.)<p>Attracting visitors is hard. Getting good speakers is harder. You can&#x27;t just let the &quot;evangelists&quot; speak, or your talks will be advertisements. Worse than sponsors!<p>Low-cost, single-track, single-evening events for fifty people or so (= small event) are possible. They&#x27;ll just not have any significant impact. (They&#x27;ll <i>definitely</i> not have an impact without lecture recordings.)<p>I can say from experience that low-cost, non-profit, moderate (500+ people) events are possible even without listed sponsors or paid talks but have to be grown over many years and require goodwill from everyone (venue + various organizations and student groups) around.<p>And Congress is special, you can&#x27;t duplicate it easily. It&#x27;s grown over decades, it&#x27;s the largest European hacker conference now (and btw: so that niche is filled now). They know in advance that they&#x27;ll sell all tickets. It&#x27;s prestigious. It attracts top-notch speakers. That would have attended anyway, of course. _Everyone_ _wants_ to help (time, money, equipment, and favors you can&#x27;t just buy with money). It&#x27;s not for profit. Dozens of volunteers begin working on it days to months before the Congress, a select few full time. Some are experts; you couldn&#x27;t afford to pay them. Multiple hundreds of visitors volunteer on-site, working for the fun of it, free water and a special t-shirt. And it still costs 90€&#x2F;ticket.