<They could just spread out what would be the lump sum payment over 3, 5, 7 years.>

We should remember that this is not your typical license buying. All these companies have been infringing for god knows how many years. And they need to pay for that. And it ought to be steep enough that early birds are tickled pink. IMHO the cost of the license ought to be a lump sum to pay for past infringment and recurring royalty payments for future use. IMHO Opty