Honestly, I think the Spider-Man ship has long sailed.
It may have looked like a more likely outcome during Phase 1, or even as early as last year, but I don't think we'll see Spidey in the MCU at this point until the rights revert.
First, I don't think Marvel would want to associate themselves with a dying franchise. TASM2 was the least successful Spider-Man film, both critically and monetarily. This could have a big affect on TASM3. Then there's the fact Sony wants to release 2 villain spinoffs prior to it, a very risky shot in the dark at this point that even Webb fans are skeptic of, and if those fail that puts TASM3 at greater risk.
Second, I think the MCU's need for Spider-Man has reached its lowest. That's not to say they wouldn't need him at all, just that he isn't as much of a necessity today as he was in the MCU's previous history. The gap between Iron Man and their other properties is shrinking. Cap is almost up there, Guardians became a top franchise, Doctor Strange is on his way. Marvel is turning more and more of their characters into A-lists.
Third, and this kind goes in hand with the second point, I feel like Marvel is at a point where they want full creative control over their properties, and would prefer starting fresh than using another studio's version of their characters. Judging from their recent films and the way Phase 2's been structured, I think that's the case.
Fourth, the rumor overall seems preposterous. "Soft" reboot or not, there's no way Sony would reboot again so soon, for obvious historical reasons. Plus Garfield's performance is also generally well received, despite the franchise's reception as a whole. So why would they replace him with a new actor that would be a complete wild card and with no setup?
Obviously I liked TASM2, and the idea of seeing Garfield in full costume next to Tony and Cap makes me giddy, but I really don't see it as a likely outcome.
