guess it's true what they say about hardware vs software. you gotta pick one to be good at, and the other is going to suffer for it, to varying degrees. (inb4 someone mentions Apple. Apple is a hardware company. Their software's alright but it's full of bugs and they're simply not as good as it as they are with hardware.)
E-commerce is hard. I worked at a company where we could use 1% of infra at its peak every day of the year except 15-20 days. We knew exactly when floodgates will open, and we still would suffer extra high latency or even downtime.
e-commerce is hard. that's why we get paid so well. hiring the smartest teenager that your nephew knows to setup some bullshit for $15/hr vs hiring a senior SRE at $100+/hr, when it directly leads to lost sales is a choice.
the senior part also comes after having failed to scale in production, and learning the lessons there, leading to a site that stays up on the next black Friday/cyber Monday, and stands up to various ddos attacks. (this was before Cloudflare, mind you)