With 20-30 people on staff if I were responsible for that architecture today. I would need:
A MySQL instance with read replicas (we had that back then onsite)
SQL Server for a some legacy projects - we had those too.
File Transfer family for FTP transfers and some automations around that.
Web servers and load balancers.
SQS and probably Lambda. Back then we used MSMQ and later MQSeries and a home grown application servers that took care of asynchronous message processing.
Web servers - a couple of EC2 instances and a load balancer and these days because of how the internet is probably WAF.
We would have needed something to orchestrate our ETL jobs. Back then we ran on 15 physical computers we would probably use something like AWS Batch today.
And of course S3.
You see how quickly your needs escalate once you are doing any real workloads?
The next smallest company I worked for had 50-60 people this was between 2018-2020. We sold access to aggregated publicly available health care provider data as well as some other health care related data. Our micro services were used by large health care companies as the backend to their websites and mobile devices and one new customer could increase the load on services they subscribed to by 20%.
Here we also needed multiple MySqL databases, CloudFront, WAF, Cognito, ElasticSearch, Redshift for large analytical loads, EC2 for some legacy software, S3, ECS for the microservices, Lambda/SQS and step functions for some ETL jobs that scaled from 0 to hundreds of thousands of transactions, Cognito for authentication, etc
You might not remember. But around March 2020, health care providers websites were being hit hard because of a little virus that was going around, the scalability that we put in place came in handy then.
Do you propose that we should have hosted all of that on some VMs?
You need to find the right balance between an expert IT team and cheaper employees. Using pre-baked cloud services is always easier, requires less management, but the operational expenditure is higher while the staffing cost might be lower. Where the company is based will also impact the professionals you'll have access to - there are places where you can have highly skilled people, and places where you'll struggle to even fully staff your IT operation.
> Do you propose that we should have hosted all of that on some VMs?
What do you think Amazon uses to run the services you pay for? Unicorns?
