Comment by ButlerianJihad

> one of the ways to prove einsteins theory

> scientists worked out the theory could be easily proven

Theories aren't proven.

Einstein, working from previous theories and models, wrote his hypothesis or proposal of General Relativity. This, too, gained consensus and gave rise to mathematical models. The models made predictions, and the predictions have been largely confirmed to date. It has proven to be a robust theory without notable falsification.

https://en.wikipedia.org/wiki/Gravitational_lens

Therefore, the theory enjoys popularity and prominence, and a good reputation in the scientific consensus. There is no "proving a theory" but the models had predicted the gravitational lensing phenomenon, and empirical observations confirmed these predictions as reality, and science marches on.