Which is to say, more likely than not, the wizard can do nothing; they can waste time and maybe roll some dice, that will not have a meaningful impact on the outcome of the encounter in any way. Wizards don't have the stats necessary to make meaningful use of a dagger, and even if they did, the damage is irrelevant because they aren't a combat-specialized class and they never get Extra Attack. Thunderclap offers a Constitution save to negate. Steel Wind Strike, if I recall my obscure supplements correctly, would require them to be some sort of weird gish that could already use a sword; and the fighter wouldn't bother trying to choke that sort of melee combatant in the first place!
It is in the Xanathar's Guide to Everything, the "first official expansion" of the game. You don't need to be a gish. And offer a Save is how the spells usually work.
See that there are 22 spells without Verbal components for wizard only. I wouldn't call it exactly "powerless" or without options. There are plenty of options. Further, those spells advantage fall into meaninglessness if you suddenly ignore the Verbal components althogeter
If your DM let you get away with that, then that's on them. It's not a reflection of the game at large, or how the rules work at any other table!
I will say that, if your house rulings allow you to disarm someone and get rid of their weapon entirely as one action, then being able to take shut down a wizard entirely as one action would have precedence at that table.!
It falls under the Interact with an object. See
https://mobile.twitter.com/JeremyECrawford/status/542134515909414912
You are perfectly able to retrieve, grab, kick or otherwise interact with the weapon in the floor. And it doesn't take an action at all. Heck, you could even step on it, if you're concerned with timing. Feel free to look at the rules. If it is at 5 feet of you, it is within your melee reach.
Here's my ruling, as a DM: If you want to choke someone in combat, then it needs to be a surprise attack. They can't know that there's an enemy nearby, or else they would be on general combat alert, which would foil the attempt. Then you can make a Stealth check against their Passive Perception to get behind them, at which point a successful opposed Athletics check will allow you to cover their mouth in such a way as to prevent spellcasting with a verbal component. I'd even let you restrain them with your other hand, while you're there.
Once combat starts, getting your hand around someone's neck is exactly as difficult as applying a dagger to their neck - you need to get through their Hit Points before you can disable them.
It seems sensible enough. It isn't exactly my cup of tea, though,as it seems very restrictive. But, then, as it is the same as pulling a dagger in it's neck, then I'll have to make an attack. And I don't have to take it at disadvantage, furthermore: I could grant myself advantage knocking prone the wizard first, also without disadvantage. And I could look at the terrain, looking for a water source, to grapple and then make a swirly.
Then, if I want to disable casting with material components, then I only have to disarm the wizard, without disadvantage, and as a part of an attack if I'm a Battlemaster and interact with an object to kick or stomp into the caster staff, rod, crystal or whatever without further checks. Goodbye fireballs and lightning bolts.
If you put me against the ropes and say "the object fall out of your reach" then a shove (shield or extra attack, heck, even as an action surge, if I don't have any of those), again without disadvantage, moves the caster 5 feet, and
then interact with the object as part of the movement. Or a grapple, and move the wizard out of place, away from the arcane focus, at half your movement. I believe that it is best at disabling a lot of casting than several grapples with disadvantage.
Again, entirely RAW.