When Trump talks about a “rigged election”, he may well be speaking to those voters who think they cannot make a difference with their one little vote. However, hundred/thoudands/millions of water droplets make up a tsunami.
Trump also knows that the reason why dems pursue voter fraud so wantonly is that the GOP will not (perhaps cannot - because of a stupid consent decree) pursue remedy for it.
Finally, given what we know happened in the dem primary process, NOT talking about a “rigged election” is an act of accepting a fraudulent election.
You may be right that Trump thinks people will identify with him by saying the election is rigged. However it can reinforce people’s beliefs that they can’t make a difference in a rigged system. Or maybe it is an emotional ploy. Dunno. I just know it makes no logical sense to say it if Trump really thinks he will win.
I would love for Trump to win—and then immediately start setting up a new party for his reelection. That IMO is the only way a real GOP alternative would be successfully launched.