Broadcom were making $$ from 1GBASET and were slow to develop/release 10GBASE-T, they held the market back and encouraged SFP+ since they did sell those chips. Intel/Cisco were inclined to wait for BRCM chips. The startups that developed 10GBASE-T (Solarflare initially led, then Teranetics, Aquantia emerged) were not successful quickly. Eventually Aquantia managed to partner with Intel & survived. Both Solarflare's PHY technology & Aquantia ended up being acquired by Marvell, Aquantia for significant $$ last year. Teranetics circuitously ended up as part of Broadcom. The rest of Solarflare was acquired by Xilinx.
10GBASE-T wasn't a good fit for data-centers due to the high power/latency. So those customers went direct attach / SFP+ / optical. Which drove those prices down, and made them more attractive, further delaying 10GBASE-T volumes. Data centers got used to expensive cables, (relatively) cheap/simple low-power, low-latency transceivers. 10GBASE-T was a solution looking for a problem.
Eventually the 2.5G/5G Ethernet for Wifi back-haul opened the copper market up - those technologies reuse almost everything from 10G. Also automotive Ethernet too. Chip/power scaling and increasing volumes for Wifi/ datacenter deployments has eventually driven down the cost to a point where 10GBASE-T is becoming more widespread/attractive.
The initial sales/marketing strategy for 10GBASE-T failed, sadly, and it has taken a long time to recover.
These are theoretical speeds that don't include modulation/protocol overheads nor interference. When it comes to wireless the rule of thumb is to usually expect a third of the advertised bandwidth.
HDMI max length is 3m, Thunderbolt is longer but requires an expensive active cable for really expensive fiber optic cable.
So for now gigabit plus some dedicated faster links where needed is plenty and cheap.
It's not just a simple cable and plug to connect something with 10Gbps, you need SFP+ then these extra adapters, then the cables.
I see that 2.5Gbe and 5Gbe will be the upgrade path for people to go with at home. I'm certainly going to upgrade to 2.5Gbe in the coming months.