Is Charlie Baker Bailing Out?

Granted he has lots of money on hand, and can raise millions more in legit and funny-money, indeed his chief strength as a candidate is his fundraising operation...yet I wonder, save a brief half hearted attempt to gin up a challenge to Ed Markey in 2020, we aren't hearing a lot about Charlie's future plans.
Which are to say the least, limited,  he is hated by the National Republican Party, he can hardly hope for an Ambassadorship let alone a Cabinet Post.  He'd need to start making moves now, if he wanted Ed Markey's Senate Seat, and I don't see a lot happening along those lines (I could be wrong though).
Granted the senatorial kaleidoscope remains clouded as long as Senior Senator Warren is running for President, potentially she could win giving Baker a shot at an open seat or a more cynical opportunity to appoint himself to the Senate temporarily and make the race as an incumbent.
After that, he could run for reelection, in 2022, he has plenty of cash on hand and no reason not to make that race. It is however the least creative option but then Baker has little imagination so it cannot be ruled out based on the scant evidence to date.
So I wonder maybe he is bailing? Ergo this is his last term...He is pressing for a real estate tax that'll be used to harden the Commonwealth against Climate Change (a rare good idea given shifting weather patterns). That has to be a revenue decision anathema to the GOP Primary, its also the sort of decision someone who isn't running again might make...
Then again Lt Governor Karyn Polito has been quietly settling up old campaign debts, that is always the first thing one does when one is needs to start fundraising in earnest...because you are envisioning an expensive state wide race.
On the other hand, Baker is as usual refusing to endorse his mentor Bill Weld's quixotic bid for the 2020 GOP Presidential Nomination, bespeaks a desire to keep peace with his own State Committee (a hotbed of pro Trump ne'er do wells) and thus keep his political options open.
So Maybe Baker is out, my only question is, will he serve out his second term or find an excuse to resign and hand over the governorship to Polito so she can run as an incumbent circa 2022?