I would like to know what exactly you do on your FIOS connection that would require such a large connection? I have already cut the cord myself and find it very difficult to find the need for such bandwidth unless I want to view illegal content. Netflix/Amazon/Roku type services only require maximum of 5-7 Mbps.
Even VUDU requires at least 9Mb/s for three bar HDX. Vudu has been around for about five years now.
Now multiply that by a family of five that may all be doing their own thing, and the bandwidth you need grows alot.
And me I'm not doing anything illegal online but I have the 150/65 tier on FiOS. The higher upload speed allows me to backup to my cloud storage much faster. Although if they would have had a 65/65 tier I would have picked that. I'm by myself so I don't really need the 150Mb/s download speeds. but I have easily maxed it out when downloading a bunch of updates for my PCs and electronic devices.