If you recall AWS didn't scale instantly originally either.

We had super bursty traffic, and had to go with Google Cloud (very early days! [0]) because you'd need to communicate with AWS and pre-warm the ELB capacity of your expected bursts.

We did a dead launch to 60 million customers (0 to 60 million, no organic growth phase) this way. I wouldn't want to do that on a VPS.

[0] https://cloudplatform.googleblog.com/2013/11/?m=1