The only thing they gave away for free was a PowerPoint viewer software. Same with Word and Excel.
These are multi-billion dollar product lines, why would MS ever give them away for free? If you received it without paying, you likely bought a PC with Office bundled in. Somebody paid for it one way or another.
Mobile is a different business model, as people are used to paying nothing or very little for apps. It's similar to what used to be called "shareware" or 'trialware' back in the day -- apps with a restricted set of features, designed to entice you into buying the full thing.
These are multi-billion dollar product lines, why would MS ever give them away for free? If you received it without paying, you likely bought a PC with Office bundled in. Somebody paid for it one way or another.