That way you haven't installed pip, you installed just the easy_install i.e. setuptools.

First you should remove all the packages you installed with easy_install using (see uninstall):

Copyeasy_install -m PackageName

This includes pip if you installed it using easy_install pip.

After this you remove the setuptools following the instructions from here:

If setuptools package is found in your global site-packages directory, you may safely remove the following file/directory:

Copysetuptools-*.egg

If setuptools is installed in some other location such as the user site directory (eg: ~/.local, ~/Library/Python or %APPDATA%), then you may safely remove the following files:

Copypkg_resources.py
easy_install.py
setuptools/
setuptools-*.egg-info/

to fully remove those you can use sudo apt purge python-pip python-dev <-- this will delete all the files/directories/binaries created by that package

apt-get / apt (side-note: no actual difference of the two, see What is the difference between apt and apt-get?) is independent from the individual packages you might install (which is logical at second sight). See apt-get install for different python versions. That is on purpose.

pip2.7

+++EDIT: It seems that the solution for pip does not work, since I got a "Permission denied" after really executing the example commands.+++ Also see this that has no answer.

If you want to uninstall an old pip, you should use

python2.7 -m pip uninstall pip for getting rid of pip2.7 (for example). and yes, "pip2.7 can uninstall pip2.7", this as a proof:

~/myfoldername $ pip -V
pip 20.3.1 from /home/myusername/myfoldername/venv/myvirtualenvironment/lib/python2.7/site-packages/pip (python 2.7)

~/myfoldername $ python2.7 -m pip uninstall pip 
DEPRECATION: Python 2.7 reached the end of its life on January 1st,
2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support pip 21.0 will remove support for this functionality. Found existing installation: pip 20.3.1 Uninstalling pip-20.3.1:   
Would remove:
    /home/myusername/myprojectname/venv/myvirtualenvironment/bin/pip
    /home/myusername/myprojectname/venv/myvirtualenvironment/bin/pip-2.7
    /home/myusername/myprojectname/venv/myvirtualenvironment/bin/pip2
    /home/myusername/myprojectname/venv/myvirtualenvironment/bin/pip2.7
    /home/myusername/myprojectname/venv/myvirtualenvironment/lib/python2.7/site-packages/pip-20.3.1.dist-info/*
    /home/myusername/myprojectname/venv/myvirtualenvironment/lib/python2.7/site-packages/pip-20.3.1.virtualenv
    /home/myusername/myprojectname/venv/myvirtualenvironment/lib/python2.7/site-packages/pip/*
Proceed (y/n)? n 

pip3.7

~/myprojectname $ python3.7 -m pip uninstall pip 
Found existing installation: pip 20.3.3 Uninstalling pip-20.3.3:   Would remove:
    /home/myusername/.local/bin/pip
    /home/myusername/.local/bin/pip3
    /home/myusername/.local/bin/pip3.7
    /home/myusername/.local/lib/python3.7/site-packages/pip-20.3.3.dist-info/*
    /home/myusername/.local/lib/python3.7/site-packages/pip/*
Proceed (y/n)? n

python2.7

Of course, that is not possible for python itself, you need: sudo apt-get remove python2.7

~/myfoldername $ sudo apt-get remove python2.7
0 upgraded, 2 newly installed, 402 to remove and 1 not upgraded.
Need to get 97,3 kB of archives.
After this operation, 387 MB disk space will be freed.
You are about to do something potentially harmful.
To continue type in the phrase 'Yes, do as I say!'
 ?] n
Abort.

From this link:

easy_install -mxN <PackageName>

That means, execute:

easy_install -mxN pip

Then, you can manually remove the .egg files or directories, that should be located somewhere in .../Python/2.7/site-packages/[PACKAGE].egg.

You also check the similar question How do I remove packages installed with Python's easy_install?

I had the same problem, but I solved using the command below:

Copysudo python -m pip uninstall pip

Pip currently ignores uninstall commands that try to uninstall something owned by the OS. It doesn't error out, like it does with a missing package. So, now you can uninstall with the following process:

pip freeze > dump.txt

Edit the dumped file to remove any -e "editable install" lines, everything after the == sign (%s;==.*;;g in vim), swap the new lines for spaces (%s;\n; ;g in vim). Then you can uninstall all un-owned packages with

cat dump.txt | xargs sudo pip uninstall -y

I had to do this procedure twice, because a few packages were installed in ~/.local/lib too.

A one-liner to accomplish this:

pip freeze | grep -vP '^(?:#|-e\s)' | sed 's;==.*;;g' | xargs -r sudo pip uninstall -y