As long as there is an ROI, they'll keep pumping out sequels.
Delaying any sequels could actually endanger the ROI by decreasing brand awareness, and increasing production costs.
And by your "if it gets made at all" you seem to be expressing a doubt that there will be a The Amazing Spider-Man 2. I've seen nothing to indicate that there's a possibility there won't be a sequel.
Men in Black 3 is more complicated, as they lost a lot of money due to delays and false starts. That represents a problem for sequels. The production budget would include stuff like rejected plans for sequels. Any costs from Tim Burton and Nicholas Cage's plans for Superman Lives are part of the production budget for Superman Returns.