"For a Linux user, you can already build such a system yourself quite trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software."
"The only problem is that you have to install something."
I don't think these things really inhibited Dropbox from taking off.
No, those criticisms probably fundamentally shaped Dropbox's marketing message, if not also informing them of where to take their product.
When people post negative criticism, it's because they find the topic important. They find it important enough to evaluate your product. You have to ask yourself whether or not their criticism has any grain of truth to it. And regardless of the answer, it's very important information.
If the answer is, "they don't understand what I'm trying to do," then you've failed at marketing. Your message is garbled and it needs work. There's no such thing as "if you build it, they will come." That movie was about a literal miracle. You need marketing and you need to get good at it.
If the answer is, "they don't understand how early the product is", then their criticism is probably based on a valid reason (expressed poorly) and you probably released too early or with too many features. Minimum Viable Product is about what is viable, not what meets your vision. Either your broken features are necessary and you released too early, or they are not and you need to cut them completely. Better to have no feature than a broken one that makes people bitch at you.
That only leaves, "yes, I recognize that their criticism is based on a valid reason (expressed poorly)". You can pretty much count on people being poor communicators 90% of the time. So your choice becomes to let their failings as a communicator push you into discounting what they have to say--and thereby harming your product--or ignore the packaging and focus on the message--and make a better product for it.
Nothing about either of those criticisms changed the product or its messaging. Nor did they need to.
Criticism is sometimes just invalid. The idea that you can "trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem" is, well, wrong.
First Dropbox attempt: https://news.ycombinator.com/item?id=8863
"For a Linux user, you can already build such a system yourself quite trivially by getting an FTP account, mounting it locally with curlftpfs, and then using SVN or CVS on the mounted filesystem. From Windows or Mac, this FTP account could be accessed through built-in software."
"The only problem is that you have to install something."
I don't think these things really inhibited Dropbox from taking off.