To remove editable in tree view you must use only tree string like below :

<tree string="Phone Calls" >

if you want to remove via inherit then try below exmple:

        <record id="view_form_editable_list" model="ir.ui.view">
        <field name="name">objectt.form.editable.list</field>
        <field name="model">object.object</field>
        <field name="inherit_id" ref="view_ref"/>
        <field name="groups_id" eval="[(6, 0, [ref('groups_if_any_in_tree_view'),ref('groups_if_any_in_tree_view'),])]"/>
        <field name="arch" type="xml">
            <xpath expr="//field[@name='one2manyr_line']/tree" position="attributes">
                <attribute name="editable"/>
            </xpath>
        </field>
    </record

In groups_id you can add that groups which are in tree views fields so when this all applied group is active then editable is removed from tree view.

Correct solution is:

<?xml version="1.0"?>
<data>
<xpath expr="//tree" position="attributes">
                <attribute name="editable" />
            </xpath>
</data>

i have had a little bit different problem, remove the editable from a tree view. but i hope this helps somebody who are facing the same problem.

to remove editable from an existing tree view, like from Attendance List in Odoo 13 like this

<?xml version="1.0"?>
<tree string="Employee attendances" editable="bottom">
                <field name="employee_id"/>
                <field name="check_in"/>
                <field name="check_out"/>
                <field name="worked_hours" string="Work Hours" widget="float_time"/>
            </tree>

use this code

<xpath expr="/tree" position="attributes">
                <attribute name="editable"/>
            </xpath>

I have the same issue and I am looking for a solution. If you have found anything please let me know. for the others what I want to do is to be able to open form in treeview witch have editable="bottom/top". I think it's a bug in V8 because this still possible in V6.1.

Regards.

As I have had the opposite problem - make an existing view editable by an inheritance - many thanks to Thorsten Francke! Your answer gave me the hint after hours of searching ... So maybe this helps somebody one day ...

In the inherited view do:

<xpath expr="//tree" position="attributes">
    <attribute name="editable">top</attribute>
 </xpath>

Regards