I created this account with an e-mail address I lost access to several years ago. I can't migrate to a Microsoft account and will eventually lose everything I have built here. Is it possible to completely transfer everything I have to a new account?
Yeah. Sounds like you should message https://pmss.emc.gs/ about your issue. We would be able to transfer your stuff to a different account. There is nothing we can personally do to help with the migration part though.
You may want to try contacting Minecraft support. However, if that doesn't work out, you can contact Senior Staff at pmss.emc.gs with the details. They should be able to move your residences, vault contents, rupees, and other things to a new account. Edit: chicken is a ninja!
Same boat as you! No access to email, and no idea what I put for "favorite pet" either. My recommendation for you is to get a perm voucher for your main CrimRyuken plots, get chicken to transfer tokens, and then farm a stack of Crim heads/make a bunch of signature books for the memories later.
With that being said, till the deadline of migrations is announced - there isn't an urgency to move stuff over to a different account. I would encourage you to continue exploring what options there are to provide sufficient verification to migrate, even without email access. We (SrStaff) will be ready to help when your options are exhausted.
I thought I was the only one with this problem. I'm trying to get back my two old accounts, but nice to see that there is help if needed.
I would bet that there is a substantial amount of Minecraft players with similar issues, even on EMC. Many people created an account when they were too young to already be using an email address, I reckon.