This isn't a reasonable argument at all. Martínez and Everton obviously worked hard to secure Lukaku. Amongst United's failed transfer dealings in the summer, we couldn't even complete a loan deal for a Real Madrid backup player in Coentrão.
And it's really foolish to suggest Moyes would be producing the same results as Martínez has at Everton. For one, he's never shown anything near resembling the bravery Martínez has against top sides, neither as manager of Everton or Manchester United. Pressure and other such terms used to excuse Moyes are really poor, there is enough quality in the United squad for results and performances to be significantly better. Moyes has indeed crumbled under the pressure of being manager of Manchester United, but managers with a progressive playing style and fearless approach exude confidence and earn the faith from their players. Moyes has failed to do this, and has taken a side believing they can win in any circumstance, to one of cowardice, zero belief, and complete and utter disjointedness.