That's why if you use cloud software you use companies that are well established and profitable.
Frankly I don't understand the hatred of cloud services on this forum. Is it an age thing? Culture? So many people think that their data is somehow safer on their $99 external USB hard drive than on Amazon's servers. Very few people know how to implement proper backups and security anyhow. Seeing as how, for a business, you rely so heavily on cloud services (whether you know it or not) then you're kind of screwed if the internet goes down anyway.
Granted, I see how it may not appeal to people who only need to track their stuff in their one lab on one computer. Or those that have shoddy internet connections or some such.
So really you have a few risk factors:
1) Quality of internet access: varies by region/person
2) Longevity of company: do your diligence, don't put your data into a company that's liable to be out of business in a week. I imagine any worthwhile inventory tool will let you export your data locally.
3) Security of company: The elusive HACKERS . Your personal computer is at far greater risk.
4) Accessibility of data: Depends on the company, see again point 2. When is the last time Amazon "just went down?" When's the last time all your local DNS servers "just went down" leaving you unable to access anything?
5) Safety of data: Pretty much every internet service that exists runs on Amazon AWS. Again, your data is much safer there than it is on your home computer.
Maybe I'm biased living in an area with pretty good, solid internet. I just don't get the fear. For an inventory tool to be useful you need it to access the internet anyway, unless you plan to download all product data from Digikey somehow or you deal only with internal part numbers.
Amazon does not appear to have an online parts inventory service, nor does Google, nor does Microsoft. Many people have already been bitten by services evaporating from one day to the next. The fact that Amazon hosts the service does not mean they will host it tomorrow. They want to get paid. If a customer packs up shop, they will not hesitate to pull the servers. If the service is provided by the big three themselves, there still is no guarantee it will be around tomorrow. Myriad examples exists of services being abandoned or replaced. Even various physical products have been rendered completely useless because their required cloud services were pulled.
In many cases you might be able to backup the data yourself, but you still would not have the infrastructure to do anything with it. If things roll over, a company might need weeks to substitute the infrastructure, which might very well be the end of the business. There is nothing you can do about that, while you can do something about the risk of storing your things on a USB drive. People being stupid with their data does not detract from that. In all cases you need to think about data security and take appropriate measures.
The 'hatred' is not as unfounded as you purport it to be here. The problem is that, nowadays, anything and everything is moved towards the cloud, even if that is not the most optimal solution. Cloud services have a place in the modern IT world and can be great in certain situations and user cases. However, currently it is a buzzword and everyone is tripping over themselves to get on board and force their portfolio into that ubiquitous cloud shape. When all you have is a hammer, well, you known the rest. Not even the greatest oscilloscope in the world makes for a complete and adequate tool kit on its own.
Of course, there is also the discussion of data harvesting. Some people are fine with every company collecting, compiling and selling their personal and behavioural data. However, many are fairly uncomfortable with it. When you use a cloud service, there is very little you can do about it if and when that happens. It would be safe to say that most online services do something of that nature. In many cases, big data has become the core business and the product a means.
Reliability is far from perfect, even in areas with great internet reliability. I know of several companies that migrated to Office 365, only to turn around and go back to a more traditional set-up. They experienced too many outages or performance was not up to par, even when combined with a mature infrastructure. In their cases, it was just not the right tool for the job.
In conclusion, people having a distrust of the cloud has nothing to do with age, culture, unfounded fears, bad internet or other irrelevant factors. Instead, many people have very well considered reasons or real world experiences that have made them wary. It would be too easy to dismiss anyone hesitant to go all in as a naysayer.