It seems Google Drive does have something like this, as I also had Google Drive, the hacker deleted those also, and Google was able to recover my files. Most hacks are dealt with within 24hours, so this would be a safeguard. Perhaps it is just like a recycle bin in the background the user doesnt see, that lasts 3 days. There is a solution to this, and Dropbox should impliment it: a simple time delay of 3 days for all 'permanent deletion' which is done from the web version. If it happened to me, it could happen to anyone. Its clear this was the modus operandi and a checklist for the hacker, to delete all recourse for backup to encourage ransom payment.

They took control of my computer through a backdoor with RDP or similar, all they did was open my own browser on my computer and Dropbox Web was already logged in. Note: the hacker did not have my Dropbox password to access my web version.

My interest is not to bash dropbox - but to warn others - if a hacker gets access to the web version of your dropbox, you are screwed.

Nope but Dropbox boast on their website they are a solution to ransomware.

Dropbox ransomware protection