THIS! YES.
I was just going to write a post somewhat saying the same thing. I have tried to think of every possible scenario in which Wayne would have motive to murder TS without MS's knowledge/involvement/direction and not a single scenario works. (And let's just say he did. MS would have figured it out and turned him in. I don't care how loyal you are to your best friend--or possible brother/cousin. If that person kills your wife right under your nose, you turn that person in. And you say something to her family when the arrest is made. Unless you wanted your wife dead.)
Two thoughts on insurance:
1) It's true that an personal life insurance payout + practice life insurance policy might equal less than TS's lifetime income. (I dunno that for sure.) BUT, ins is basically like getting free money and he could continue to earn and get money from the practice with LS's energy healing.
2) I think I read here that over the past months MS's name was put on titles of multiple companies that MS and TS owned. Would he be collecting multiple insurance payouts on her death? Maybe in that case (and with the additional $1 mil he and LS were hoping to get from account--the arrogance!--it would be a giant payout that would far surpass TS's lifetime earnings.
(PS-I can't go there with the possible involvement of a family member. It crossed my mind at one point, but I just can't. I can absolutely go the direction of a staff member!)