LTE can be as high as 150Mbps down...
This statement is wrong ... mildly said.
LTE in its first standardized incarnation (I believe it was called release 8 or R8 ) indeed defined max DL speed to be 150Mbps ... but that was like 10 years ago, when devices could only use single carrier (max carrier bandwidth is still 20MHz and max modulation scheme in DL at that time was 64QAM, MIMO was limited to 2x2 ... which indeed offered around 150Mbps).
Today it's possible to reach much higher: max modulation in DL is 256QAM, MIMO rank is up to 8x8 (but devices are falling behind, there are handfull of devices supporting MIMO 4x4 on select frequency bands), so if stars align nicely it is possible to reach up to 400Mbps using single FDD carrier. When one throws carrier aggregation into the mix, 1Gbps can be reached quite easily. Nope, beam-forming doesn't help that much at reaching high speeds for a particular user/device, but does help to reach higher "sector throughput".
All of the above can be, more or less, reached in a lab. Real life drops numbers at least by one third due to various reasons (inter-cell interference, high pathloss, reflections causing intra-cell interference, poor separation of MIMO "branches"). And multiple users all fighting for same set of resources. So even if modem's air interface supports higher speeds, it is quite likely that those speeds won't be sustained for longer periods of time ... and ethernet (or USB if you want) interface can be slightly slower than theoretical maximum of the radio.