Pathfinder was not all that expensive by space mission standards. The total budget was only about $200M or so, which was an order of magnitude less than typical prior missions.
Also, while I was not personally involved in Pathfinder, I was in the research program that led up to it. We were doing things that had never been done before, including the first use of an off-the-shelf commercial operating system on a space vehicle. We were under tremendous time and budget pressure, and so was Pathfinder. The idea that an intermittent system reset could be written off as a hardware problem is entirely plausible.
Also, while I was not personally involved in Pathfinder, I was in the research program that led up to it. We were doing things that had never been done before, including the first use of an off-the-shelf commercial operating system on a space vehicle. We were under tremendous time and budget pressure, and so was Pathfinder. The idea that an intermittent system reset could be written off as a hardware problem is entirely plausible.