AI will probably dominate the everything where the process is well known and BORING. Even if better mechanisms (security, processing, protocols) take place, there will always be issues between humans and machines.
For example here is a good example, about how computers and humans make each others situations more complex.
I've spent 2 years as a founder at my start-up and it seams like a drop in the bucket. I was just able to turn around twice and all of a sudden, I'm 50% though my vesting period. But then the other founders are 50% or more though their vesting period as well.
It may well take 8 years to get this company to IPO. 4 years seams standard, but it feels awfully sort for some reason.
Dividing up equity is an ugly issue, because sometimes it's more about availability of talent, contract clauses, time (4 years is not a lot of time). Best to get it right the first time.
It's hard maintaining great security because, security and speed are usually in direct opposition.
In terms of hardware/OS:
Turn off everything incoming except for HTTPS, SSH, and ping (optional).
Make sure everyone uses SSH keys (no passwords)
In terms of programming, focus on security roles is tricky at first. So you want to be careful in describing how user roles or user permissions work in your site.
Create a staging server with test data that mimics your production site (nearly exactly). Any penetration company company will ask you to sign a "This won't hurt anything", when smashing up your server.
Another place to focus is how backups are copied, who can access the data, etc..
This is a really big topic. Your insurance company when you apply will have an excellent check list.
This is really hard to do. The problem is the scalability is that personal project's just don't get to being say.. 500gigabytes big. And they don't have some 1000 programs asking questions, nor do they have junior engineers working the db.
This problem is akin to stress testing a fully functional system.
Personally, when I've had this itch, I work on learning map-reduce in mongodb/riak.