[JohnBooty]

If your legacy app is incompatible with modern browsers, yeah, that's got to change. No debating that, really.

But,

1. That may or may not mean a full rewrite of the app. Even in terrible old legacy apps, there usually is at least somewhat of a separation between the backend and frontend logic.

2. While not exactly uncommon, the scenario you describe is a subset of legacy apps. A lot of them work just fine, other than the fact that they're not in the latest version of the latest cool framework.

[Foobar8568]

I doubt all the code behind, dataset ridden ASP.NET got so easily replaced.... Or most JSP etc. There is an absurd amount of applications out there, hacked together over the last 20 years.

[colemannerd]

I highly doubt they work as well as an engineer believes. If there are no absolutely no user requested changes - even something as simple as support a new browser type or device type - then maybe. Otherwise, I've seen this viewpoint kill multiple companies because it lead to uncontrollable technical debt.