Why do companies look for alternatives to Arc.dev?

Arc.dev is a well run, transparent platform, so the reasons are rarely complaints about quality. They are structural. Arc.dev connects you to a single vetted individual, commonly $60 to $80 per hour, with a $300 refundable deposit and a 20% fee if you hire the developer full time. For that you get one person, not a team, so interviewing, project management, code review, and QA remain your responsibility, and the pool is smaller than an open marketplace, so niche or senior stacks can take longer to fill. Teams building something ongoing often want a team and delivery accountability rather than a single seat.