I'd say
every single company sitting on billions of assets are on the target list. Facebook, Apple, Microsoft, Google, Amazon, Uber, everyone (although Microsoft is the least attacked here). But the illusion here is we only see the big guys, we rarely question the smaller guys, unless someone publishes a CVE or publish a disclosure.
Many users are paranoid about ToS and how companies (esp the big guys) make money either by learning your behaviors (search preference, sites you visited) or selling your data to a partner (Foursquare, although they claim to only sell location data which are anonymous). We have a blind-trust with service providers. We let service providers to collect everything about ourselves, but internally they can decide whether to discard "sensitive data" early on or not during data processing (but web logs would have the trace).
Has anyone every inspect the traffic, or reverse the API in (e.g. Fitbit?) What about file sharing companies? Are they storing your data in a secure way and without reading what's in your file? What about sites that let you compare prices across multiple stores? What about medtech startups? What about when the company is acquired?
Because the giants are more eye-catching, we don't see the smaller guys; but we are willing to give away sensitive and private data to the smaller guys because? If the argument is "well the big guys should have known better and have more resources to do the right thing", then I argue that by 2017 the new startups are doing the right things (not making the same well-known security flaws for example). I have doubt; I doubt many achieve 50% of what is on the imaginary checklist. The claim "we build MVP" is the equivalent of the big guys saying "we know what we are doing, don't worry."
No, we don't know better. No, your MVP should be secure enough so users can trust you. I almost never try a newly launched service because I really don't want to be a lab rat. I am sorry if that sounds cynical, but I don't trust myself doing everything right. If you let me choose between a new file sharing startup vs others, I'd go with either Dropbox, Google Drive or OneDrive (FWIW, Google is replacing Drive with a new service). Why? Because if the big guy is compromised, well, shit, thousands or millions will be affected. The least cynical version is, well, they are too big to do stupid things (of course not true in reality).
Our biases create illusions.