Nope. You're forgetting the cost to the company is the burdened labor cost (https://en.wikipedia.org/wiki/Labor_burden), not just wages. Payroll taxes, benefits, office space and equipment, etc. can add another 30-40% to the cost of wages.
This doesn't have any SLAs nor is it critical software either. 24/7 oncall is completely unnecessary.
The main scaling challenge here is serving and bandwidth, both of which are handled by their CDN. I expect 5 figure costs for that but the rest of the platform is very expensive.
Just because everything is in AWS doesn’t force you to use all of AWS services.
But since images are immutable, this is a perfect use-case for lambda functions fronted by a CDN.
Do you actually run pay-per-action campaigns, or do you provide a dashboard for the customer data ?
To manage infrastructure at that scale themselves they'd need someone who knows DevOps. To write services at that scale they'd need someone who knows backend engineering and micro services. Then they'd need to be able to have 24/7 on call rotations for when things break. And of course, like any rewrite it seems like a "couple month" project until you get into the details and it becomes a two year project. Soon you've got a full 6+ person team and are paying them a lot more than $600k/year.