It seems likely that BA will order more A380s to replace at least some of these.

They already bought their A380s. They're not buying any more. The 747 will most likely be replaced by A350-1000s or 777-9s.

BA wants to buy additional A380s - they just haven't yet been able to agree on the price. For an airline with a slot-constrained hub (Heathrow), it would be a step backwards to replace 747s with smaller aircraft as this would reduce their overall route capacity.

https://www.bloomberg.com/news/articles/2018-01-19/airbus-is...

They've been hollering about that for awhile now, the deal was supposed to close by Feb 15, then April 15, and now talks are suspended altogether. If it isn't dead I'd be surprised.

UK government just approved an extra runway at Heathrow, so capacity there (and onto NYC) will increase a fair bit.

It will, if it actually gets built. The Heathrow third runway will be subject to the mother of all protest movements and legal challenges, so it'll be a decade or more before it could possibly get built - well after the remaining 747s are due for retirement.

Maybe the A380 program will continue for many years, but it seems unlikely the program as a whole, including development costs, will ever earn a profit.

How does a plane end up being overweight? And how did the weight get reduced on later models?

The same thing happened with the first 787 examples, as well. What I read was wiring to support testing equipment that couldn't easily be removed

That's what I want to know, and why can't they be retrofitted to match the specs of the later models?

It's not always cheap to remove 5 tonnes of wiring. You need to count downtime and the cost of removal proper (disassembly, testing, reassembly, more testing) and compare it with the difference in price of scrapping it and replace with another model that's, perhaps, a better match for your desired capacity and the difference in the operational cost over the plane's lifetime. There are two-engine planes that promise to almost match the actual usage of the 380 for a lower operational cost.

Your last part there is wrong: as covered in many comments here, the A380 is still selling, in fact to the same carrier that's not renewing the leases on these early models. So it does still have a niche that it excels at; the problem is just that the early models have too much weight compared to current models.

This isn't about the A380 vs. other models, this is about old-A380 vs. new-A380. I was just asking why it wasn't feasible to retrofit the old ones to match the specs of the new ones, which these carriers do want and are buying. I could understand if we were talking about cars, where there's a well-tuned assembly line and it's almost never cost-effective to retrofit, and the unit cost is actually shockingly low when you consider the complexity and cost of components, but large aircraft aren't like cars. (Aircraft assembly plants make a few dozen a year, car plants make hundreds of thousands.)