The only purpose that impeachment proceedings would serve would be to rile up the other side and, therefore increase the chances of getting Trump re-elected.
Yes, investigations should still occur, but they should be for the sole purpose of getting transparency for the American voter and letting the voter give the final verdict on whether or not Trump should be re-elected.
Democrats should be open about this purpose. They need to put to bed any future talk of impeachment NOW, and say it simply will not happen, in taking away any potential fuel for Republicans to rile up their base. Democrats should instead focus on the issues for 2020 and beyond. The spectacle of impeachment proceedings will take away from that and divert media attention away from that, not to mention split the party base, which should remain in lockstep on everything. Trump would get drunk in glee over any discord between Dems.
Besides, the Senate would acquit him.
And, besides, even if the Senate somehow got their spine back and removed him, chances are it would occur close to the election anyways.
And, besides, even if the investigations were miraculously wrapped up much quicker and impeachment proceedings occurred a lot sooner, and the Senate learned conviction a lot faster, we would just have Mike Pence in charge.
Impeachment is just a formal inquiry. Just because a president is impeached doesn't remove him from office. The steam on all this is turned way down anyway after what Nancy said.
Besides, it's far better to threaten impeachment and rail on and on about impeachment than to actually do it. You heard what she said, Trump isn't even worth it. I would have curious to see what the fuss was about.