Single post in Two-Factor Authentication

I'm incredibly thankful don't get me wrong. I understand the need for this, hence why I'm asking. Considering this site is relatively old, and especially considering that paypal/money is often used here, why wasn't 2FA implemented sooner? I assumed there was already a layer of security like this to protect users because of the use of money here, but to find out that there wasn't all this time...That genuinely worries me. I never searched for it because I didn't need it (as my password is very unique to here anyway, and I don't use money to pay for in-game currencies). I understand if you guys were busy and what have you, but this website is years old, including a site transfer.