Surprised that free access to the full index has lasted as long as it has ..... theres no such thing as a free lunch - except for the co-hosting of the FreeBMD d/base, which has to remain free under the conditions of its provision.
FreeBMD itself - now it has the resources - is a more flexible search engine - hopefully, transcribing will continue at the same pace.
Ancestry - like the other 'major' players - are in it for profit.
You
are an asset - a revenue generating one

One difference is the computing resources that Ancestry have compared to the others .... how many can sustain the userload and scope of searching ?