As much as paid acquisition is powerful, the cost of acquiring customers WILL become more expensive over time through it. Enter engagement and retention, your saving grace.
Let's be honest, engagement sounds A LOT like retention. Don't you engage customers so to retain them? As great as it is to get thousands of customer in the door, that doesn't matter much if you can't keep em. Learn the difference once & for all.
"Marketing is a tax you pay for not building a phenomenal product." I'm not going to tell you what you want to hear, but rather what you should hear: marketing accelerates growth, it doesn't cause it.