A premise, that while factually true, is missing the key factor that the BBC have the rights to broadcast the Olympics, while ITV do not. It's like asking why the BBC sent more people to the Olympics than my local newspaper, or why there are more bus drivers in London than my village. You're not comparing the work that those people are doing, just the raw numbers. Therefore your comments are based on a fallacy, and your conclusions are therefore invalid.
I can guarantee that ITV would send more people to the Olympics than the BBC of they were the rights holders instead. Being a commercial company has nothing to do with it (indeed, you should see the numbers the Americans send over).
The latency of the high bandwidth feeds (5Mbit is usable, 10Mbit starts to be good, 50Mbit is higher than would be sent over satellite for a primary programme feed) is less of an issue, as long as the timings stay consistent as you can delay feeds appropriately where you put them together. You can use simultaneously a low latency feed at much lower bitrates to give you confidence / talkback / return video feeds and reduce delays between participants.
4G connections have become fairly standard for remote inserts, primarily in news, but also other programming. I believe the Timeline kit being used by BT Sport was originally bought for coverage of women's football, with all the production happening at their base and all cameras fed back over 4G (most matches are single camera jobs).
Basically the clever bit is the linking up of the various technologies that have become standard over the last few years in different areas of broadcasting, and then translating that to having your production staff in separate locations as well as your contributors.
The BBC have also been using a lot of IP connections over standard broadband connections for their radio broadcasts, using software like Luci Live.
As I said before, Openreach have stopped going on to customer premises, so an upgrade or new line isn't going to happen at the moment.