I have just run into this issue as well! I am totally panicking, as my site relies on good internal search functionality!
After finding this page on forum here, I reached back out to SS (was the 4th agent I talked to today) and I finally got a real response (the others were blanket replies saying that the issue is being forwarded to engineering and they will work on it).
The last agent agreed that it's been an issue with 7.1 since the beginning, that the search doesn't work for text blocks, image titles or captions or most content on layout pages!
I am mortified after spending hundreds of hours on my site.
How can this issue have not been fixed by now ~ I mean seriously!?
At least, if they CAN'T fix it, there should be an upfront disclosure, on their site, that alerts people to this problem, when people are choosing between 7.0 vs. 7.1 and/or between SS and another platform (that can handle the basic functionality of internal search).
FYI Apparently it's not an issue for 7.0, but those templates can not do what 7.1 can, design-wise.
I feel like I have potentially lost 100's of hours of work, time and money and really don't understand why SS can't fix this bug! How can we get through to them, to have this resolved?