Onboarding Free Trial email sequence: only FIRST email matters?

Analyzing my free-trial onboarding email sequence and noticed a trend, and want to ask if you see the same in your products or elsewhere.

Some context.
For our QuickAdminPanel (tool to generate adminpanels for Laravel framework), we have 14-day free trial with limited functionality. Over that period we have Drip sequence of 7 emails, spread over 2 days each:

1. How to easy generate X - link to the product to use the function
2. What modules we have - link to the product to use the function
3. Help about file upload - useful article
4. Help about datatables - useful article
5. Help about roles and permissions - useful article
6. 2 days left - want to extend your trial for another 14 days?
7. Last day discount (sounds pathetic, I know, but it kinda works)

And looking at open/click rates, they are pretty stable: 20-30% open rate and 5-7% click rate for ALL emails.

But for the first time now I analyzed direct correlation to PAYMENTS, and it seems that people pay only in three cases:

• Pay on same FIRST day if they like the tool (they don't need email sequence)
• Pay after FIRST onboarding email
• Don't pay at all and then come back months later when they actually need/remember the tool

My point is that it seems that only FIRST email matters. It's like pinging users "Hey, you didn't forget about us?" and they go "Oh right, right, ok where's my wallet..."

Do you notice same/similar behavior in your trial sequence, or elsewhere on the web?

Cause I feel the need to wipe almost all sequence (or change it to something completely different) except for the first email.

Thanks for the opinion!
Povilas