After almost becoming the first coach to lead a Scottish team to a major title on Saturday, he issued a reminder that the champions were the nearly team not so long ago, and that their subsequent breakthrough - they have won six trophies in the past seven seasons - should inspire his Warriors, and their burgeoning band of followers, to believe that similar riches are in store for them.
Aspirations are everything but should not be confused with dreams and Glasgow might want to be careful about using Leinster as the measure of their dreams. To want what the Irish side have borrows a little too much from fantasy.
Townsend is right to underline that Leinster - Heineken Cup winners in 2009, '11 and '12 and RaboDirect PRO12 champions in 2008, '13 and '14 (runners-up in 2010, '11 and '12) - were not always the embodiment of what professional provincial rugby can look like.
In the early 2000s, Leinster still changed in Portakabins and played in front of an average crowd of fewer than 3000 at Donnybrook Stadium.
At the time, this represented significant growth because in the late 1990s, Irish provincial rugby had still been so low-profile that Munster and Leinster once met at Dooradoyle in front of 700 people.
Fast forward a decade and the rival provinces met in the semi-finals of the 2008/09 Heineken Cup. It was O'Driscoll v O'Gara and O'Connell and there was no rugby stadium in the world big enough to satisfy the public demand to bear witness to this collision of cults.
In the end they settled on the venue of Croke Park, the home of Gaelic games, and the attendance was 82,208. It is difficult to find a parallel in world sport for that pace of growth.
Munster and Ulster were always a draw, but the idea of rugby fans who lived on the east coast of Ireland wanting more than the Irish national side in their life was a slow burner. Leinster, we now know, were a sleeping giant but, for a long time, that snooze was too enjoyable.
With the growth of the Heineken Cup, crowds at Donnybrook grew steadily until 2005 when Leinster moved to the Royal Dublin Society Showground - it was previously used primarily for an annual horse show - and had a regular attendance close to 6000. Because the product was improving, Dublin was awash with money and there was no rival professional sport in town, the brand matured year on year and the business grew.
Now, as Glasgow bask in the reflected glory of their first five-figure crowd, Leinster have about 14,000 season-ticket holders and are fully intent on increasing that number to 18,000 in order to justify a 5000-seat expansion of the RDS to a capacity of around 23,000. Every time an English or French side visits, they command all of Aviva Stadium's 50,000 seats.
The Edinburgh-Toulouse quarter-final in 2012 attracted 35,000 people, suggesting there is a market here for big rugby days that do not involve Scotland, but can a team at either end of the M8, encased as they are in football heartlands, ever achieve even a fraction of the exponential growth seen in Ireland?
If the Scottish Rugby Union's profound challenge is to make domestic rugby self-sufficient, for both of their teams to turn occasional fans into regulars by showering them with success without having to pick up the cheque, then Ireland, again, is probably a dangerous place to look for inspiration.
When Leinster were playing at Donnybrook they relied almost entirely on central Irish RFU funds to run a team. Glasgow, having proved they can sustain healthy crowds of 5000 to 10,000 throughout a season, could perhaps now support a professional rugby team without the SRU providing the lion's share of the finance, but they would not be competitive.
Leinster, whose growth has been a miraculous marriage of money, talent and demographics, might never win three Heineken Cups in four years again but it would take a historical event of meteoric significance to undo all the advances they have made.
Glasgow should keep looking above them, they must keep looking above them, but looking directly into the sun will only interfere with their vision.