To me, the word "CAN" and "ARE" imply the same meaning when used in this context.
You can use "ARE" if you prefer.
To me, they are completely different. "Can" suggests the possibility or future prospects. "Are" suggests currently doing. For example ...
For myself, I "Are/am" currently making the most revenue with B4X as #1. I "Can" see this still being the best revenue stream for the development work I'll be doing in the medium-term future, as well, as long as the language can develop, mature significantly, and fill some holes without getting side-tracked too much. If not, then it may just get relegated to #3 usage.
#2 is irrelevant as I own the company.
#3 is the "Can" ... IF you
can get lucky and hit upon an idea/marketing scheme/pure dumb luck to get a popular app ... the sheer numbers involved when those elements come together can dwarf any of the other 4 options in your poll. For myself, I don't think of programming for #3. Maybe when I retire or sell the company.
#4 seems to be hampered by support costs and the inherently changing landscape of developers tools and languages. Especially in the iOS and Android market. I've done this for 2 past development languages and, while most of those efforts were successful, it just wasn't worth it as a revenue stream in the end. Maybe for hobbyists or if you can cast a wide net as a more general purpose developer tool but not for one specific (especially small) developer language/tool. I have several classes I've developed and use in my own projects that I wouldn't mind releasing to the B4X community, for example, but I have no time or interest in supporting them right now. It'd be terrible to do that.
#5, for myself again, is an integral part of most of my B4X programming. I think you meant it as a standalone tool for web development, though. For that, I don't see that as being any more profitable for a developer than just straight HTML/CSS/scripting and long established backend programming (ASP, .NET, PHP, etc.). If B4X is all a programmer knows and you're deploying on your own servers then that's fine. But, if you're developing for a client on their servers then you'll likely run into problems. Why hire, for instance, a B4X developer just for web development (without a special reason like interacting with the other B4X tools) when you can pick up an HTML/CSS/PHP/etc... programmer off the street (or contract one from anywhere in the world) in minutes and it'll run on existing web servers without much or any changes?
As for #6, that's obviously not the case. Any programming language or tool that is newer, backed by a small company/organization, and with fewer developers is going to be a challenge for professional developers to find the right fit or incorporate into their programming. But it does happen. It's just up to the professional developer to find that fit. Which is often the difference between a professional and not.