It really depends. There’s a lot of SPAs which are practically unusable on a bad connection simply because it’s a challenge to even get the whole thing loaded in the first place. There’s been several occasions where I’ve had poor cell connectivity and a huge chunk of the web was effectively off limits due to this.

So in addition to aggressive caching, I’d say keeping the app’s file size down is also pretty important to making it useful on poor connections. That’s frequently something that’s barely optimized at all, unfortunately.

I work on an SPA with hundreds of screens. We package it using off the shelf tooling with barely any configuration. All of the code and styling is still far under a megabyte gzipped.

So unless it is an all text app, the size of the code bundle is probably going to be quickly dwarfed by the size of media like images, animated images, or videos.

If a site has an SPA with a, say, 3mb code bundle, I think in most cases, that’s not an architecture issue. It’s probably an issue of poor engineering and switching to a MPA is not suddenly going to make those engineers competent.

All three comments to this thread have missed the point that OP said installable SPA, not website SPA. This means the primary bundle is downloaded offline and only API network requests are necessary.