Of course it's possible to win without a HUD. There's nothing magical about a HUD that makes you a better or winning player in and of itself. Until you learn to use a HUD properly it can actually cost you.
HUDs are just tools that, if leveraged properly, can help automate what tends to be a tedious manual task (keeping notes/stats on players). You still have to interpret those stats and make good poker decisions. Far far more valuable than the HUD is the tracker, which is what will make you a better player when studied away from the table.
Where HUDs really shine is with multitabling, because you can't possible keep track of that many opponents coming and going across multiple tables when you have to act every second or two.
And it's pretty silly to suggest they should be banned. Virtually everyone who thinks that don't really understand HUDs and how they're used. The sites like Bovada
that "don't like HUDs" (but don't ban them either) don't like them because they're a staple of winning players, and these sites are adamantly anti-winning-player. So they figure if they take steps to thwart HUDs, it will drive the serious players away while favoring the re-depositing, never-withdrawing recreational fish. I think that idea has kinda backfired on them though, because plenty of solid players still crush the fish there and withdraw without using a HUD. As I said, it's not really necessary especially if you're not massively multi-tabling (which you can't do at Bovada anyway, I think 8 is the max?). I just don't play there out of principal.
It will probably surprise some of you to know that most other sites/networks embrace trackers and HUDs and even fund their development. If a new poker site
comes online and wants PT to support them, for instance, they approach PT and have to pay them to add support.