Lufthansa 440/441

I get almost all the international flights to and from Houston (IAH) over my house daily. One of the flights I look for is Lufthansa 440 to IAH and 441 return to Frankfurt. I love seeing that huge A380 soaring over me. Well I guess they changed to a B747-8 sometime last month and I didn’t notice. Any reason why?

Most likely reason is that the load factor went down and they replaced the A380 with the next smaller aircraft type. Why did the load factor go down?
Speculative, but… more airlines flying to Houston, so fewer connecting passengers in FRA. More hassle from US Immigration, so fewer passengers interested. More direct flights to other places in the US (say, Austin) so again fewer connecting passengers.