MCU: What if Tony Stark had died in that cave..

I loved the 'What If' one shots that Marvel do and it got me thinking,

What if Tony Stark had died in the cave in IM1 and never finished making the first suit..

Would the Chitauri have ever invaded?

Would Thanos be lurking in the background still?

Would Earth just be unprepared without a fight?

I think I've pin-pointed Earths involvement with the MCU on goings to when Odin cast out Thor to Earth thus starting Lokis interest in Earth?

What if hey?..