There are numerous examples of the Senate being able to circumvent the rule directly that requires 60 votes to end a filibuster, and the threat to expand the nuclear option to other areas. Then there are some political reasons that many Senators on the Democratic side may find common cause with the GOP. Finally, filibusters are rare, not the least of which is that they are taxing physically.
In November 2013, Senate Democrats used the nuclear option to eliminate filibusters on executive branch nominations and federal judicial appointments other than those to the Supreme Court. Given that personnel is policy this allows the GOP to staff through appointments basically anyone the Trump administration likes throughout the executive branch and federal courts. Note that when Harry Reid used the nuclear option, the rule change only used a simple majority of votes. The precedent has been set then to change this rule if Democrats become too obstructionist--with the judge being GOP senators solely.
Second there are numerous types of votes that require simple majority such as budget reconciliation
Reconciliation is a legislative process of the United States Senate intended to allow consideration of a budget bill with debate limited to twenty hours under Senate rules. Because of this limited debate, reconciliation bills are not subject to the filibuster in the Senate. Reconciliation also exists in the United States House of Representatives, but because the House regularly passes rules that constrain debate and amendments, the process has had a less significant impact on that body.
Fast tracking of trade agreements is another such example. Bills that automatically expire at a given date must be passed to reauthorize and re-fund those initiatives usually require Democrats to gather majorities to do so. For example, the World Bank legislation is on such a time frame.
In addition, the Democrats are at a structural disadvantage on legislation because the President is of the same party and is not likely to veto much. So if a law does pass with 51 votes its likely to become law. Debt limit debates, threats of government shutdown, and the like are likely to become a thing of the past. Opposition parties use these tools to garner concessions, and likely there will be few.
Politically speaking it doesn't get better for the Democrats either. PBS states
The election two years from now had already looked difficult for Senate Democrats, who must defend 25 seats compared to just eight held by Republicans. The Democrats’ list includes two independents, Vermont’s Bernie Sanders and Maine’s Angus King, who align with them.
Of those 25 senators, 13 are from states Trump captured or narrowly lost. Among those are Maine, Michigan, Pennsylvania and Wisconsin, which hadn’t backed a GOP presidential candidate since the 1980s...Five Democrats are from states Trump easily carried, by 19 percentage points or more — Indiana, North Dakota, West Virginia, Missouri and Montana.
“They should be terrified,” Ward Baker, executive director of the National Republican Senatorial Committee, the Senate GOP’s political organization, said of the Democrats
I don't think these Senators are likely to filibuster any of Trump's agenda. Some may join with the GOP on important issues like the reform of the unpopular ACA.
Finally there is the filibuster itself. The cloture vote is really a wink-wink, nod, nod, to threaten the filibuster, at which time the motion is usually tabled if the vote totals don't reach 60. However, if it's not tabled, someone has to be willing actually go through with the filibuster. In other words the more the threat of cloture is used, the more likely a GOP Senate may require Democrats to actually filibuster. And given the average age of Democrats I'm not totally convinced they have the ability to do so on a regular basis.