I grew up going to hackathons and they were fairly open ended and collaborative. The recent hackathons I've attended are just a vehicle to get you to use cloud infrastructure (AWS, GCP, Vercel, etc).

More recently, teams have been attending hackathons with an already completed product, using the event to attend VC meetings instead of doing any hacking. And when they invariably win with a well done, complete product they use the media announcements to generate leads. My duct-tape and cardboard hack doesn't look very good but we designed and built it within the team we assembled 48hours ago.