cable box stopped getting connection

TV working fine.   Then the next day no connection.   followed all the troubleshooting steps nothing fixed.   Called for a support technician.  Next day he came,  replaced the box,  still not working.   He then told me that i needed to replace all inside cable (RG59) with RG6.   I don't understand how suddenly the inside wires are the source of the problem.    As my internet is working fine should I just drop cable and go only with streaming services?