Church - Substance - Faith - Saints

It has been said that Millennials are leaving the church because of substance: they want the church to change its substance.
First of all we need to understand what we mean by "substance". A quick Google search shows that "substance is the real physical matter of which a person or thing consists, and which has a tangible, solid presence".
Substance is what makes the person or the thing to exist. Without it, we will not talk about person or thing.
Asking the Church to change her substance is asking her to change what makes her Church. Can the Church change her substance since she did not create herself?
I would rather see the Church looking for the way to address the issues of the day. I would rather see the Church being real and preach the Word without compromising. I would rather see the Church going back to her roots to practice the faith once delivered to the Saints (Jude 1:3).