Conversion rate will tend to go down as you get better at marketing, which is extremely counterintuitive to many people (including marketers), and sometimes you're "running to stay in place."

"OK I need that explained explicitly."

As you get better at marketing, the barrier required to find out about you gets lower. Prior to getting good/sophisticated/scaled, the leads you get are largely sophisticated early adopters who have a burning pain and searched exhaustively.

Once you get good, you will get some leads that didn't have to make it their life's work for 4 weeks to figure out your company existed, and *even if you are nowhere close to saturating the market* you will dilute the denominator of your conversion rate with "worse" leads.

They're worse in the sense that they'll convert as a lower rate, but they're not necessarily *bad* leads; whether they're good or not depends on your standard CAC vs LTV math.

But but but but but they will not perform like your early adopters on churn rates, either.

Most businesses will attempt to counteract this by getting better at conversion to recoup some of the notional loss of conversion rate (again, a poor frame for thinking about it) and, wait for it, Charging More, because crossing the chasm ungates Basically All Of The Money.

A related factor: leads from different sources are generally lumped together in summary statistics but are often basically incomparable in terms of pre-signup and post-signup behavior.

And attribution (in complex sales especially) remains a mostly unsolved challenge.