Firefox died long ago.

It was an engine fight, and Mozilla decided not to participate.

Things cost stuff.

Except Bio-Dome, that’s free. Basic economics says that price approaches marginal cost of production.

That discussion tactic results in groupthink to a level that even coherent positions on the broad issues get obscured by conformance to factional stereotypes.

It’s really bad to support specific policies just because they sound like a kind of policy that you broadly support. I personally broadly support pro-density policies. But many specific policies that are proposed either have fatal flaws or are useless as long as a century worth of accumulated NIMBY policies exist that super-redundantly ban the sort of density increase that would actually be useful.

And to be clear, only allowing density increases without cars would be exactly the sort of nonsense restriction that would be a fatal flaw, at least in the US.

Many people have already done the math many, many times, and it always works out to be a lot cheaper to have dense urban areas.

I just moved from a dense urban area to a rural area. Taking everything into account - yes, really - things are unambiguously cheaper here. That’s a common result in the US. If you want to blame a single thing, I’d go with lack of housing supply in cities due to exclusionary zoning, but I hit some other weird figures like municipal water+sewer being more expensive than a well and septic system (again, yes, taking everything into account including construction costs).

It’s worth actually doing the comparisons to see whether car-centric living is a net positive or negative in practice in particular situations. Urban density should be a pure benefit, with economies of scale making everything cheaper. Unfortunately, cities in practice have some downsides that reduce that benefit. One major one is that centralizing services means that it’s more useful to try to get a cut of the cash flowing through the institution, and so some of the gains get siphoned off. As a trivial example, exactly zero percent of car commute expenses go to a bus driver’s union.

Is there some reason that wall won’t work fine?

Obviously. What sort of moron wouldn’t be prepared to defend themselves from angry bees or whatever Pooh was afraid of.