Market model - Portfolio risk & return

In the topic of return generating models where the formula is -

E(Ri) - Rf = βi1 x E(Factor 1) + βi1 x E(Factor 2)… βik x E(Factor k). And then after that theres a single factor model which is also known as a single index model and then theres a simplified model of signle index model called the market model which has the formula - Ri = αi + βiRm + εi. So my question is why doesn’t this formula have the EXPECTED return on the asset - i like the other formula does. Would really appreciate it if someone could help me out on this one. Thanks in advance!

It would be the expected return without the error term (εi); the error term represents the difference between the actual return and the expected return.