On a abstract level a lot of problems are business process problems and can be modeled in that way , it doesn't mean one company working one one type of problem

On a abstract level a lot of problems are business process problems and can be modeled in that way , it doesn't mean one company working one one type of problem should have excellence in another, hiring problems are very very different from freight logistics. I don't know anything about Flexport, I know about hiring tech that perhaps helps you to understand what goes behind such processes. Hiring tech usually can be grouped in 4/5 buckets. Applicant Tracking Systems(ATS) /Workflow tools, Sourcing, Screening / Selection , Offer / Negotiation and Finally on-boarding. In each category depending on type of hire(Full Time/Contract), departments/skills(tech/sales/finance etc), and geographic locations(U.S./Europe/Mexico etc) you could end needing dozens of tools. It is not unusual for a startup not have tools to manage their workflows yet, the hiring processes evolve a lot in early stage companies, they insource/outsource and shift all the time, each dept or new VP brings theirs own ideas with little standardization etc. Few startups invest in an ATS ( not just buy actually put effort to deploy) at < 500-1,000 head count. It takes a long time for all this to settle down for any growing company. Workflow tools like ATSes are systems of records designed for compliance and to help the recruiter not the candidate. That means most recruiters have little incentive to update the records of a rejected candidate into the system, they are only measured by offers made/ joined etc, once you are rejected a typical recruiter will loose interest fast, few would even let you know that properly, even fewer would know why you were rejected and update the system ( if it exists at all) . Hiring managers are also guilty, post an interview rarely do they give comments( to the recruiter after the interview) even if they do, it is even less likely that those can be be shared to a candidate. Also finally even for companies working on solving hiring problems, it is not easy to solve their own hiring process issues. It is rare for one company to be building all the tools needed by a company to hire. i.e. HackerRank/Codility may build great coding tools, but they still need to use ATS or sourcing tools in their hiring processes, and that can mean their processes are also not perfect and have similar problems.