Earlier quoted context omitted.
You update the software. If they start charging, you don't care, because you can keep your free copy. I don't know about the "huge overhead cost" of running an update now and then. ...but, the data is yours, the software is yours, the solution built on it is yours. Noone can raise the prices, noone can give unrealistic/stupid limits (eg. how many queries can you do per month in your paid/free package,...), and noone…
"I don't know about the "huge overhead cost" of running an update now and then." Clearly you've never had to go to hours and hours of change management meetings for a minor release.
If something changes, you atleast can delay the change, until you fix other components (or maybe even not update, if it's some internal stuff), because with SaaS, you have no say about it.
Even if the project becomes unsupported, you can still run the old version, until you find 'something new' (or again, keep runing the old for internal stuff).
If you build anything around a SaaS provider, they alway have yu by the balls,... be it with ever changing pricing or killing the project, "just because" [0]