Every new customer costs more than the one before
If you look at a platform like Meta, every year the cost to acquire a customer goes up and up and up. This shows up directly in your CPMs and your reach.
It shows up in your CPMs and reach
For the same amount of money you're spending to reach a thousand people, the price goes up every single year. So for the same customer you acquired last year, this year it's going to be more expensive.
Your job becomes better ads, better creatives, better conversion
Your goal now becomes making better ads, better creatives, and converting better on your landing page. That's how you try to keep your acquisition costs as low as possible. But at the end of the day, it's always going to get more expensive to target that customer.
If growth only means acquisition, it's not growth — it's an expense
If your growth strategy is only dependent on acquisition, at some point this is not growth anymore, it's an expense. You need to figure out a way to increase the value of your customers and how to reach your customers off these platforms. This is where real growth happens.