It is not feasible to rewrite it in the fancy language/technology du jour - huge waste of resources for things which already work fine and at the moment you are done you have to start again, since the IT-pendulum is traveling in the opposite direction.

We, as an industry are really bad at working with legacy code, but for a lot of us it may be the main task if we endure this line of work for some decades more.

Small problems benefit from small tools. Large problems benefit from large tools. However, small problems grow and your bet as a small problem is that your tools will grow with you.

In practice, they usually do. If they don't, you end up extending the tool or rewriting it in a larger tool.

So, our tools start small, and small companies use small tools, and the ecosystems grow together. Then, the successful ecosystems end up the next large problem toolkit.

As you're a small ERP SaaS, you're banking on growing with your customers, I presume. And you can make an argument to start on the large tools at the cost of initial velocity, but that's your tradeoff.

I really think the innovation that needs to happen is a system that has a prescribed growth path. Retool/Excel/similar that can compile to a simple app that can adapt to more complex patterns as the need comes.