This is a known Excel's issue. See Excel incorrectly assumes that the year 1900 is a leap year. Some people could tell that this is not a "bug" because it's working as intended. See Is there a bug in Excel concerning dates?
On the Google Sheets side, there isn't documentation about why they don't "repeat the same error" but it could be related that they prefer to make it follow the OpenFormula standard.
Historical and Sci-fi time travel authors, alsos should have in mind that the calendar isn't the same all the time and for all the places and that some Excel and Windows versions have other Date and DateTime issues.
Date and DateTime
A Date is a subtype of number; the number is the number of days from a
particular date called the epoch. Thus, a date when presented as a
general-purpose number is also called a serial number. This
specification does not specify the exact value of the epoch, but
implementations MUST support all dates from January 1, 1904, through
December 31, 9999 (inclusive). Portable spreadsheet files MUST NOT
assume any particular epoch values. Since dates are simply numbers,
they can be added, subtracted, and so on like other Numbers.
Subtracting one date from another produces the number of days between
A Datetime is also a subtype of number, and for purposes of formulas
it is simply the date plus the time of day.
Note: Excel for Windows usually uses 1/1/1900 as serial number 1,
while Excel for Windows uses 1/1/1904 as serial number 1. "Excel 2000
in a Nutshell" page 330 discusses time storage in Excel, including
this, and noting December 31, 9999 as a date both support. Excel 2003
copies a bug from an old version of Lotus 1-2-3; both act as though
1900 was a leap year. Thus 1900-02-29 has the serial number 60, and
all date calculations on or before that date are wrong by one day.
This specification does not require copying this bug. See "Excel 2003
Formulas" page 143.
Excel 2003 is unable to deal with dates before January 1, 1900; again,
there's no requirement that other implementations have this
limitation. Implementations that wish to support a broader range of
dates, yet also the same numbers for most dates, could do so by using
negative numbers as dates before the epoch (be careful, because a time
inside the day adds to the beginning of the date).
In OpenDocument Format a date, datetime, or time value in a cell is
stored in a special locale-independent format based on ISO 8601; see
the OpenDocument specification for more information. Implementations
may choose to store dates in a special type that is distinguishable
from other numbers. However, from the point of view of a formula, a
date, datetime, or time value is simply a subtype of Number, and must
follow the rules of this specification. Most countries use the
Gregorian calendar and ISO 8601, but not all. Note that applications
must be able to convert text, in a variety of formats, into date
TBD: In earlier times dates were dependent on the location of the
event, which is not necessarily the current locale. In particular,
different countries switched from Julian to Gregorian on different
dates. This creates a challenge if it is desired to represent dates in
formulas significantly before 1900. One solution is to use the
"proleptic Gregorian" calendar, which is simply the current Gregorian
calendar indefinitely extended in both directions of time. Python
2.4's date types use proleptic Gregorian, and points to Dershowitz and Reingold's book "Calendrical Calculations" for various means to
convert that to other calendar systems. The advantage of proleptic
Gregorian is that it is locale-independent, works well with ISO 8601,
and there are defined ways to convert between it and other calendars.
If the goal is just to store dates, and not compute differences, then
it can easily represent arbitrary dates without complexity in the
basic spreadsheet implementation. If conversions are needed, they can
be embedded in spreadsheet formulas -- which is the right place to put
them, because the current locale is often not the locale of the event,
and only the person entering the data will know the correct locale.