Apostasy is related to Aqeedah.
Sunnah is related to Action.
Do you understand these concepts?
A person can shave his beard all his life BUT still not leave Islam. In fact he may actually defend Islam
A woman can walk around uncovered all her life BUT still not leave Islam. In fact she may actually defend Islam
Do you recognise that? By the way, they are both sinners...
Relaxation in following the Sunnah is related to weakening of Emaan which may or may NOT lead to apostasy. This weakness of Eemaan is an important issue which needs to be addressed but Apostasy is an Aqeedah issue. I am not denying that it is not important or that it does not need addressing.
I am also not denying that it can lead to apostasy.
No matter whatever the issue, the steps given are equally important.