> Tottenham Hotspur Stadium has 20,000 network access points, 1,849 IPTV screens, and 519 CCTV screens. It hosts about 63,000 viewers
A decent part of that is probably important to be working on the day of a football match. They already own a suitable building, probably with decent backup power, so running their own servers seems both more reliable and cheaper than renting.
> A decent part of that is probably important to be working on the day of a football match.
Otoh, if they only need the servers to run while guests are attending matches (and other events), it looks like they do about one event a week from their calendar [1]. Why pay to have the server 24/7 if you only use it for maybe 6 hours a week.
With that kind of utilization, cloud may well be cheaper.
Reliability you can argue either way. Onsite has the benefit that there's no external network causing problems; however for a site like that, you're likely to have redundant high capacity internet providers so that's less of an issue. Certainly, when there are server issues, having them onsite provides more agency, but I don't think that means it's more reliable.
[1] https://www.tottenhamhotspurstadium.com/events