An example: I once worked for a company that was successful in the translation space. Most freelance translators were using Word with some expensive plugins, but the company made the choice to use an app made in-house tailored to translation and that gave them a competitive advantage (faster iteration, less mistakes), so they basically replaced Word with an in-house solution. And their "product" was still the translations, not their hidden software (Of course this was back when Translation Management SaaS weren't popular).
Of course I've seen the opposite happen as well: I know a SaaS company that were in the business of selling blogs and CMS software. They had built their own blogging/CMS from scratch in the span of two years, but after six months launching, they pivoted to be a Wordpress host. Whoops, looks like customers just wanted a Wordpress anyway. They're doing ok now btw. (btw: I know that's a terrible example, since they turned out to be a service company rather than a software company).
Point is, writing a WMS or TMS would make sense for a non-software company if (and only if) it had completely novel ideas that would put them ahead of the competition. Of course that's a rare thing but still a good space to be explored!
Interestingly, that's probably another lesson on mistakes that kills startups: thinking that the only thing able to replace X is an exact replica of X.
Also guilty of number one, kind of. But that is more due to family /economic situation than a lack of a co-founder.
Regarding programmer and platform. There are so many cloud solutions out thereby now, unless softwareis your product, there is no need to develop it in-house. Take warehouse management and transportation management. Unless you want to built a new WMS or TMS, but build a service, just use the stuff that exists. Which make the programmer a guy able to appraise and implement said software. And like the programmer, one of the founders should be good at doing that.