Te form and ru form of verbs when used with potential form

Question

What's the difference between using the te form of a verb with the potential form as opposed to just the ru form?

E.g.

食べてられない、待ってられない
食べられない、待てない

Answer 1

食べられない is just negative-potential, but 食べてられない is a colloquial version of 食べていられない, which is negative-progressive-potential.

• 待てない: I can't wait.
• 待って(い)られない: I can't keep waiting.
• 食べられない: I can't eat it.
• 食べて(い)られない: I can't stay here eating it.

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EDIT: Some more examples:

• 見られない (= 見えない): I can't see it.
• 見て(い)られない: I can't watch it any more. / It's unbearable to see.
• 起きられない: I can't get up (out of bed).
• 起きて(い)られない: I can't stay awake.