Android Gravity Center in RelativeLayout Doesn't Work Like LinearLayout

For RelativeLaout:

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center">

    <TextView
        android:id="@+id/a_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="8dp"
        android:text="Sam"
        android:textColor="@color/black"
        android:textSize="30sp" />

    <TextView
        android:id="@+id/b_textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="16dp"
        android:text="Kate"
        android:textColor="@color/black"
        android:textSize="30sp"
       android:layout_toEndOf="@id/a_textView"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Show"
        android:textSize="30sp"
        android:layout_toEndOf="@id/b_textView"/>

</RelativeLayout>

Result: Not centered perfectly

For LinearLayout:

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    android:gravity="center">    //<- here, child Views are the same

Result: Centered perfectly

Question: Why so and how to make RelativeLayout to achieve the same result in LinearLayout by ONLY MODIFYING THE ATTRIBUTES IN RelativeLayout?

You have different solutions but changing some attributes in the children views.

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    ..>

    <LinearLayout
       android:orientation="horizontal"
       android:gravity="center_horizontal">

        <TextView/>
        <TextView/>
        <Button/>

    </LinearLayout>
</RelativeLayout>
        

or:

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    ..>

        <TextView/>
        <TextView/>
        <Button
          android:layout_alignBaseline="@id/a_textView">

</RelativeLayout>