well, you can always lower the capital for each node from 5 million to say 1 million, that would give you more nodes...
also, you should always plan for things to go wrong and take longer than expected, it might take a long time before f1cx dex is built and running and even longer for it to have big trading volume.
also with your current model, the rewards pool would only be a 40% ROI on the 5 million needed.
right now on masternodes online there are 480 MN coins and 433 have a bigger ROI than 40% per annum.
earlier you were comparing MTC node incentives to banks, but this is crypto, you have to compare your self to the other MN coins.