Well, not exactly sold, but 'at the mercy of'.
You should always keep in mind the disadvantages of relying or learning too much flash; yeah, learning is not bad, but you should be careful what you're learning.
Remember that Flash, shockwave are Adobe product, it's Adobe's property, but your work (your work on Flash), your skills, or you heavily flash ridden website rely on these products. It depends on Adobe how your flash work displays, and also depends on Adobe on what devices you flash work is displayed. Any security vulnerability in Adobe's product may be exploitable via your flash work, and unknowingly you (and Adobe) will be to blame.
And these are not hypothetical examples, but these have been already proven. For starters, Adobe is no longer supported on mobile devices and on Linux, it's been discontinued and your flash (or future flash work based on future versions of flash) work wont work on these devices, even though you want to.
To businessmen with a company's website (who very commonly use flash), all this means that your company is already more dependent on yet, more companies, which no business owner likes; your customers may have a bad experience for your eye-candy flash animation and might not even consider your products simply cause your website didn't open on their device, or they were having technical issues related to flash. To most businesses, a customer wants to see your products, get product information and find information on your products easily, what will they do with eye candy? Even Facebook and Google doesn't have that, why do you need it? People want your website to open fast and provide them the information they need as fast as it opened, they don't want to get hogged by slow animation and loading times which makes your website impossible to view with slow internet connections!
To businessmen with a company's website (who very commonly use flash), all this means that your company is already more dependent on yet, more companies, which no business owner likes; your customers may have a bad experience for your eye-candy flash animation and might not even consider your products simply cause your website didn't open on their device, or they were having technical issues related to flash. To most businesses, a customer wants to see your products, get product information and find information on your products easily, what will they do with eye candy? Even Facebook and Google doesn't have that, why do you need it? People want your website to open fast and provide them the information they need as fast as it opened, they don't want to get hogged by slow animation and loading times which makes your website impossible to view with slow internet connections!
These are the reasons for why not Flash/Shockwave or any propitiatory plugin. With these technologies, you're never your own master, Adobe is your master and Adobe is all about money, not about you.
So go for HTML5 and webgl, they're all about you, all about standards and benefits to the public without any political or business motivation.