“But if you’re in my position, you need at least 2-3 months between the first and the last step. If your attendance is conditional on speaking at the conference (for example, if your company will only sponsor you if you’re speaking), then you need a minimum of 2-3 months between when speakers are notified and the conference starts.”
An Indian passport holder needs a visa for most countries, plus bank statements, years of tax returns and an embassy appointment that can be months out. The application alone runs from a few hundred to over 1000 US dollars. A conference that notifies speakers six weeks before the event has already picked who gets to attend. It just never wrote that down as a policy.