The move to 10GBASE-T has been slower than molasses. In the corporate data center however, lots of hardware is for sale with network boxes as low as $500 and PCIe network cards under $40.
Marvel only is offering quad port logic which is being aimed at network hardware vendors. They do not even have logic for server cards.
A 10 gigabit device will need PCIe 3.0 to allow for a single lane to have enough bandwidth available for full performance. 14nm or better would keep the power consumption low.
The Intel 82599EN is a 10 gigabit PCIe 2.0 controller. It is made on the old 65nm line and it the catalog price for it is $42 in boxes of 1000. No doubt that a 14nm version would be dramatically easier to integrate into a motherboard where PCIe 3.0 or PCIe 4.0 speeds are available which would make a single PCIe lane sufficient for use.
Right now the Broadcom BCM84881 is their single chip 10GBASE-T logic. It seems to be well represented but it has not been seen widely on network adapters where it is competitive.
The BCM84881 is about 400 pin ball grid array designed for surface mounting. The device is about 20mm square which is comparatively big for an ATX motherboard. It is also not known if thermal management is needed.
The BCM84881 and 82599EN are not being sold to consumer motherboards makers. The cost of the chips is far too much to consider except for expensive server hardware. The lack of a large scale manufacturing environment, there is not much hope for change.