This is pretty common practice here for an ISP or CLEC to want to check the inside wiring before upgrading the connection speed.
From their perspective it's good practice to stop truck roll-outs, and excessive "speed troubleshooting calls". Alot of homes have exsisting wiring from the 1960's - 1980's.
Why?
When Digital subscriber lines first hit the market, they had sub megabit speeds. (Here in PA it was about 75Kbps down and around 35 up) And could easily be transmitted over straight pair phone lines.(CAT-3)
With the progression of ADSL&VDSL and different compression techniques, and better frequency multiplexing. These technologies can now compete with other ISP connection technologies on the residential market.
As you push higher Mbps on the same CAT-3 lines. The same problems are introduced that became an issue when Ethernet moved past 10Mbps. The frequency, and data rates are just too high for cat-3. Cross-talk becomes an issue, and cat-3 IS NOT a balanced cabling system, which means it's highly susceptible to electro-magnetic interference. (Cat-3 too close to power etc).
So while it seems like a scam maneuver from your ISP, it's in your best interest to upgrade the old telephone lines to the very least CAT-5 UTP.
You can always run your own inside wiring if their technician charge is too expensive.
theres no way for us to tell. you may be quite right, but all ISPs run themselves differently, and there are plenty of reasons why a given configuration might require a home visit (though I would argue that in that case the ISP is not being-all-they-can-be with their choices for tech selection and maintenance process definition). – Frank Thomas – 2018-05-02T16:35:10.287