I Dark energy and the gravitational constant

[windy miller]

Many have claimed that if dark energy was not so small then the universe would fly apart and we wouldn't be here.
However what if you increased the value of lambda and at the same increased the value of the gravitational constant ( or perhaps the amount of matter or dark matter in the universe) could that not compensate?

 

[mfb]

Not in a way that would give a nice universe after 13.7 billion years. Gravity is more relevant in the early universe, dark energy is more relevant in the later universe. If you just increase both, the universe collapses long before dark energy would become notable. If you increase gravity a bit and dark energy massively, the early universe gets better, but afterwards the universe expands way too much.