What you're missing is that cost/complexity-wise, LightSail and EC2 are equivalent. The only difference between them is your interface to it. LightSail doesn't give you some pretty necessary knobs to kick things into a working state when the EC2 instances are having a burger. In fact, the last time I used LightSail and had a problem with unavailable instances, I just ran the ec2 api commands against the lightsail instance IDs to solve my problem.
DigitalOcean has some networking properties that make it extremely undesirable for some use cases and Linode is frequently the target of massive global DDOS. I remember well a few years ago the Christmas Eve Linode DDOS because I had to work 20 hours that day.
Thankfully it was only 20 hours because we were already in the process of moving off of Linode and we just decided to flip all of the switches to serve out of AWS. Most of the time was spent waiting on DNS TTLs.
Instance costs across all of the cloud providers are pretty competitive. Where AWS and Google Cloud and Azure are more expensive are in those "extra" services where you would be paying people to run infrastructure (elasticsearch, sql databases, etc). DO, Linode, etc, don't give you that option -- it's not an apples-to-apples comparison....and in most cases you shouldn't use some of these things. Definitely no service where you can't just pick up and go use some other hosting tomorrow. Cloud vendor lock-in is real.
