However, this increase of course would also have been the case without the new laws (as you say, as people move from SMS to Whatsapp, they have to compensate). The only difference is that they now can't differentiate between different uses of the internet, but only on the amount of data you get.
I don't think the net neutrality isn't such a bad thing price/economic wise. I'd rather have this clear system which might mean slightly higher prices for the average consumer than a system in which different prices for different uses of internet make calculating your actual costs more difficult. In my opinion, that would only give more opportunities to telecom providers to screw you over with little details, rules and clauses in their contracts -- something which history has shown they don't shy away from (rounding up every call duration to a full minute etc.).
The Telcos are using SMS money to subsidize more expensive parts of the business that people will probably opt out of if they were charged the full amount.
I don't know enough to say what those are, but you're right, the SMS money probably isn't all profit. Right-pricing SMS will probably mean that some other part of the business would be cut back (unfortunately R&D is often a victim).
When the current shareholders are pitted against the future shareholders, the future shareholders often lose.