The fact that your corporate network allows Citrix through doesn't mean that all of them do. In fact many do not.
As you well know, well-run firewalls start out with a default "deny all". And then you start adding things you allow. If they don't have an exception made for Citrix traffic from outside, you won't get it without a bureaucratic hassle.
And at many companies the corporate firewall kills Citrix. If you want to deliver a product over the net using Citrix, you will lose potential clients because of that. It is no fun calling up a prospect and finding that the group you are dealing with don't receive Citrix. You may have a perfectly good product. But you can't demo it to them. And even if you did sell them on how nice your stuff is, they won't bother because they don't have the time or energy convincing their BOFHs that they really need this.
(And yes, the company where I work looked long and hard at trying to deliver products to clients using Citrix. And for our client base it wasn't worthwhile. We, in fact, get better penetration of our core market from our Bloomberg product than we could get with Citrix. That should tell you a lot about who our clients are.)
Cheers,
Ben