[TheDong]

"emulate the old networking" is something that can't be done per customer, and the new platform makes networking per customer.

Let's say I have my aws account "account1", and my friend has their account "account2", both running classic. We could have both talked to each other's instances by their _private IPs_ even though they're in different accounts. AWS has no way of knowing those two instances are related, other than that they're both in classic.

Sure, AWS could make a global cross-account emulated flat network, but at that point, it's probably cheaper to just use the real thing, which was already built and functions... and at that point, you're not migrating them to "the new platform", but rather to "ec2 classic 2"

[londons_explore]

If there is a small number of classic users, a single special case in the code to have all classic users connected to a single network of an admin account seems very doable...

I wonder if perhaps part of the reason for not doing this was they were worried about malware spreading across that shared internal network from one VM without security patches to the next VM without security patches.

Even if that were the case, they could monitor all VM's on the classic network, and any VM which doesn't contact another users VM's for ~1 month would have the ability to do so be blocked.