Movies ended with a promise of a sequel, but still haven't had one yet

Normally these are box-office flops where they had planned a sequel, but then were dropped by the studios because of poor performance. Examples that come to mind:

Amazing Spider Man (they ended with all the badass stuff being revealed, but ASM3 has been shelved)

I Am Number 4Stormbreaker (there are a whole host of novels, but the film was atrocious)

Fantastic Four (they just rebooted it)

Green LanternHis Dark Materials (the Golden Compass/Northern Lights sequels never appeared)

The A-Team (its a damn good action movie, but didn't make much money)

These all started out with the idea of starting a film franchise/adapting an existing franchise to screen - but due to poor performance they never appeared.